Manual and automatic shift controls for transmissions

Claim 2

A transmission and control comprising; an input; an output; multiratio gearing drive connected between said input and output having selectively operable low and first ratio drive engaging devices for selectively establishing low and first ratio drives; a source of fluid under pressure; governor means providing a governor signal varying as a function of output speed; modulator means providing a signal varying as a function of torque demand; shift control means connected to said source and said low and first devices operative in a first position to control the supply of fluid to establish first ratio drive and in low position to control the supply of fluid to establish low ratio drive; manual shift control means operatively connected to said shift control means operative in a first position to position said shift control means in said first position and operative in a low drive position to provide a low drive signal; low shift signal means connected to said manual shift control means and said shift control means operative in response to said low shift signal in a shifting position and to position said shift control means in said low position and operative in an inhibiting position to position said shift control means in said first position and in the absence of said low shift signal in both said shifting and inhibiting positions to position said shift control means in said first position, said low shift signal means having operating means independently responsive to both said torque demand signal below a predetermined low torque demand value and to said governor signal at speeds below a predetermined speed to position said low shift signal means in said shifting position and responsive to either said torque demand signal above said predetermined torque demand or said speed signal above said predetermined speed to position said low shift signal means in said inhibiting position.

Claim 3

The invention defined in claim 1 and means connected to said low device and said low shift signal means responsive to the establishment of said low device to position said low shift signal means in said shifting position.

Claim 4

The invention defined in claim 1 and said low shift signal means having actuating means for independently adjusting said predetermined torque demand and said predetermined speed.

Claim 5

The invention defined in claim 3 and actuating means having one adjustable spring opposing said torque demand signal and another adjustable spring opposing said speed signal.

Claim 6

A transmission and control comprising: an input; an output; multiratio gearing drive connected between said input and output having selectively operable low and first ratio drive engaging devices for selectively establishing low and first ratio drives; a source of fluid under pressure; governor means providing A governor signal varying as a function of output speed; modulator means providing a signal varying as a function of torque demand; shift control means connected to said source and said low and first devices operative in a first position to control the supply of fluid to establish first ratio drive and in low position to control the supply of fluid to establish low ratio drive; manual shift control means operatively connected to said shift control means operative in a first position to position said shift control means in said first position and operative in a low drive position to provide a low drive signal; low shift signal means connected to said manual shift control means and said shift control means operative in response to said low shift signal in a shifting position and to position said shift control means in said low position and operative in an inhibiting position to position said shift control means in said first position and in the absence of said low shift signal in both said shifting and inhibiting positions to position said shift control means in said first position, said low shift signal means having operating means independently responsive to both said torque demand signal below a predetermined low torque demand value and to said governor signal at speeds below a predetermined speed to position said low shift signal means in said shifting position and responsive to either said torque demand signal above said predetermined torque demand or said speed signal above said predetermined speed to position said low shift signal means in said inhibiting position and independently adjustable to independently adjust said predetermined torque demand and said predetermined speed; means connected to said low device and low shift signal means responsive to the establishment of said low device to position said low shift signal means in said shifting position.

Claim 7

A transmission and control comprising: an input; an output; multiratio gearing drive connected between said input and output having selectively operable low and first ratio drive engaging devices for selectively establishing low and first ratio drives; a source of fluid under pressure; governor means providing A governor signal varying as a function of output speed; modulator means providing a signal varying as a function of torque demand; shift control means connected to said source and said low and first devices operative in a first position to control the supply of fluid to establish first ratio drive and in low position to control the supply of fluid to establish low ratio drive; manual shift control means operatively connected to said shift control means operative in a first position to position said shift control means in said first position and operative in a low drive position to provide a low drive signal; low shift signal means connected to said manual shift control means and said shift control means operative in response to said low shift signal in a shifting position and to position said shift control means in said low position and operative in an inhibiting position to position said shift control means in said first position and in the absence of said low shift signal in both said shifting and inhibiting positions to position said shift control means in said first position, said low shift signal means having operating means independently responsive to both said torque demand signal below a predetermined low torque demand value and to said governor signal at speeds below a predetermined speed to position said low shift signal means in said shifting position and responsive to either said torque demand signal above said predetermined torque demand or said speed signal above said predetermined speed to position said low shift signal means in said inhibiting position and independently adjustable to independently adjust said predetermined torque demand and said predetermined speed; means connected to said low device and low shift signal means responsive to the establishment of said low device to position said low shift signal means in said shifting position.

Claim 8

A transmission and control comprising; an input; an output; gear means drive connected between said input and output having selectively engageable low and first ratio drive engaging devices for establishing respectively low and first ratio drives; a source of fluid under pressure; speed governor means connected to said output and said source providing a governor pressure varying with output speed; modulator means providing a modulator pressure varying with torque demand; selector valve means connected to said source and having a low drive line operative to connect said source in a low drive position to said low drive feed line; low first relay valve means connected to said source and said first drive means and having a low apply line connected to said low drive device, biasing means normally biasing said relay valve means to a first position connecting said source to said first drive device for establishing first drive and low signal means operated by pressure to move said relay valve means to a low position connecting said source to said low apply line and low drive device for establishing low drive and low shift signal valve means connected to said low drive line, said speed governor means, said modulator means, and said low signal means and having a valve element and a control element movably between open and closed positions in a bore having stop means preventing movement of said control element beyond said positions, said valve element in closed position blocking said low drive line and exhausting said low signal means and in open position connecting said low drive line to supply pressure from said low drive line to said low signal means, a low force spring biasing the valve element toward said open position and said control element, a high force spring biasing said control element torward said valve element and providing an excess differential biasing force engaging and moving both elements to closed position, said control element having an unbalanced area acted on by said modulator pressure operative at and above a predetermined low torque demand value in conjunction with said excess differential force to mOve said engaged elements to closed position and below said predetermined torque demand value in conjunction with said excess differential force to move said engaged elements to said open position, said governor pressure being connected to control said valve element in all positions and operative at speeds above a predetermined low speed to move said valve element from open to closed position in conjunction with said low force spring independent of torque demand and at speeds below said predetermined speed not affecting control by said torque demand pressure signal at said predetermined torque demand.

Claim 9

A transmission and control comprising; an input; an output; gear means drive connected between said input and output having selectively engageable low and first ratio drive engaging devices for establishing respectively low and first ratio drives; a source of fluid under pressure; speed governor means connected to said output and said source providing a governor pressure varying with output speed; modulator means providing a modulator pressure varying with torque demand; selector valve means connected to said source and having a low drive line operative to connect said source in a low drive position to said low drive feed line; low first relay valve means connected to said source and said first drive means and having a low apply line connected to said low drive device, biasing means normally biasing said relay valve means to a first position connecting said source to said first drive device for establishing first drive and low signal means operated by pressure to move said relay valve means to a low position connecting said source to said low apply line and low drive device for establishing low drive and low shift signal valve means connected to said low drive line, said speed governor means, said modulator means, and said low signal means and having a valve element and a control element movably between open and closed positions in a bore having stop means preventing movement of said control element beyond said positions, said valve element in closed position blocking said low drive line and exhausting said low signal means and in open position connecting said low drive line to supply pressure from said low drive line to said low signal means, a low force spring biasing the valve element toward said open position and said control element, a high force spring biasing said control element torward said valve element and providing an excess differential biasing force engaging and moving both elements to closed position, said control element having an unbalanced area acted on by said modulator pressure operative at and above a predetermined low torque demand value in conjunction with said excess differential force to mOve said engaged elements to closed position and below said predetermined torque demand value in conjunction with said excess differential force to move said engaged elements to said open position, said governor pressure being connected to control said valve element in all positions and operative at speeds above a predetermined low speed to move said valve element from open to closed position in conjunction with said low force spring independent of torque demand and at speeds below said predetermined speed not affecting control by said torque demand pressure signal at said predetermined torque demand.

Claim 10

The invention defined in claim 6 and means to adjust the force of said high force spring to independently adjust said predetermined torque demand, and means to adjust the force of said low force spring to independently adjust said predetermined speed.

Claim 11

The invention defined in claim 6 and said low shift signal valve means having means responsive to low apply pressure to hold said low shift signal means in open position.

Claim 12

A transmission and control comprising: an input; an output; gear means drive connected between said input and output having selectively engageable low and first ratio drive engaging devices for establishing respectively low and first ratio drives; a source of fluid under pressure; speed governor means connected to said output and said source providing a governor pressure signal incresing with increasing output speed; inverted modulator means providing an inverted modulator pressure signal decreasing with increasing torque demand; selector valve means connected to said source and having a low drive line operative to connect said source in a low drive position to said low drive feed line; low first relay valve means connected to said source and said first drive device and having a low apply line connected to said low drive device, biasing means normally biasing said relay valve means to a first position connecting said source to said first drive device for establishing first drive and low signal means operated by pressure to move said relay valve means to a low position connecting said source to said low apply line and low drive device for establishing low drive and low shift signal valve means connected to said low drive line, said low apply line, said speed governor means, said modulator means, and said low signal means and having a valve element and a control element movably between open and closed positions in a bore having stop means preventing movement of said control element beyond said positions, said valve element in closed position blocking said low drive line and exhausting said low signal means and in open position connecting said low drive line to supply pressure from said low drive line to said low signal means, a low force spring biasing the valve element toward said open position and said control element, a high force spring biasing said control element toward said valve element and providing an excess differential biasing force engaging and moving both elements to closed position, said control element having an unbalanced area acted on by said inverted modulator pressure signal operative at and below a predetermined pressure at and above a predetermined low torque demand value permitting said excess differential force to move said engaged elements to closed position and on increase of said modulator pressure signal below said predetermined torque demand value overcoming said excess differential force to move said engaged elements to said open position, said governor pressure signal being connected to said bore between said elements in all positions and operative at speeds above a predetermined low speed to exert a force on said valve element to move it from open to closed position against said low force spring independent of torque demand and at speeds below said predetermined speed not affecting control by said torque demand pressure signal at said predetermined torque demand.

Claim 13

A transmission and control comprising: an input; an output; gear means drive connected between said input and output having selectively engageable low and first ratio drive engaging devices for establishing respectively low and first ratio drives; a source of fluid under pressure; speed governor means connected to said output and said source providing a governor pressure signal incresing with increasing output speed; inverted modulator means providing an inverted modulator pressure signal decreasing with increasing torque demand; selector valve means connected to said source and having a low drive line operative to connect said source in a low drive position to said low drive feed line; low first relay valve means connected to said source and said first drive device and having a low apply line connected to said low drive device, biasing means normally biasing said relay valve means to a first position connecting said source to said first drive device for establishing first drive and low signal means operated by pressure to move said relay valve means to a low position connecting said source to said low apply line and low drive device for establishing low drive and low shift signal valve means connected to said low drive line, said low apply line, said speed governor means, said modulator means, and said low signal means and having a valve element and a control element movably between open and closed positions in a bore having stop means preventing movement of said control element beyond said positions, said valve element in closed position blocking said low drive line and exhausting said low signal means and in open position connecting said low drive line to supply pressure from said low drive line to said low signal means, a low force spring biasing the valve element toward said open position and said control element, a high force spring biasing said control element toward said valve element and providing an excess differential biasing force engaging and moving both elements to closed position, said control element having an unbalanced area acted on by said inverted modulator pressure signal operative at and below a predetermined pressure at and above a predetermined low torque demand value permitting said excess differential force to move said engaged elements to closed position and on increase of said modulator pressure signal below said predetermined torque demand value overcoming said excess differential force to move said engaged elements to said open position, said governor pressure signal being connected to said bore between said elements in all positions and operative at speeds above a predetermined low speed to exert a force on said valve element to move it from open to closed position against said low force spring independent of torque demand and at speeds below said predetermined speed not affecting control by said torque demand pressure signal at said predetermined torque demand.

Claim 14

The invention defined in claim 9 and means to Adjust the force of said high force spring to independently adjust said predetermined torque demand, and means to adjust the force of said low force spring to independently adjust said predetermined speed.

Claim 15

The invention defined in claim 9 and said low shift signal valve means having means responsive to low apply pressure to hold said low shift signal means in open position.

Claim 16

A transmission and control comprising: an input; an output; gear means drive connected between said input and output having selectively engageable low and first ratio drive engaging devices for establishing respectively low and first ratio drives; a source of fluid under pressure; speed governor means connected to said output and said source providing a governor pressure signal increasing with increasing output speed; inverted modulator means providing an inverted modulator pressure signal decreasing with increasing torque demand; manually controlled valve means connected to said source and having a low drive line and a forward drive feed line and operative to connect said source in forward position to said forward feed line and in a low drive position to said forward and low drive feed lines; low first relay valve means connected to said low first feed line and said first drive device and having a low apply line connected to said low drive device, biasing means normally biasing said relay valve means to a first position connecting said low first feed line to said first drive device for establishing first drive and low signal means operated by pressure to move said relay valve means to a low position connecting said low first drive feed line to said low apply line and low drive device for establishing low drive and low shift signal valve means connected to said low drive line, said low apply line, said speed governor means, said modulator means, and said low signal means and having a valve element and a control element movably between open and closed positions in a bore having stop means preventing movement of said control element beyond said positions, said valve element in closed position blocking said low drive line and exhausting said low signal means and in open position connecting said low drive line to supply pressure from said low drive line to said low signal means, a low force spring biasing the valve element toward said open position and said control element, a high force spring biasing said control element toward said valve element and providing an excess differential biasing force engaging and moving both elements to closed position, said control element having an unbalanced area acted on by said inverted modulator pressure signal operative at and below a predetermined pressure at and above a predetermined low torque demand value permitting said excess differential force to move said engaged elements to closed position and on increase of said modulator pressure signal below said predetermined torque demand value overcoming said excess differential force to move said engaged elements to said open position, said governor pressure signal being connected to said bore between said elements in all positions and operative at speeds above a predetermined low speed to exert a force on said valve element to move it from open to closed position against said low force spring independent of torque demand and at speeds below said predetermined speed not affecting control by said torque demand pressure signal at said predetermined torque demand.

Claim 17

A transmission and control comprising: an input; an output; gear means drive connected between said input and output having selectively engageable low and first ratio drive engaging devices for establishing respectively low and first ratio drives; a source of fluid under pressure; speed governor means connected to said output and said source providing a governor pressure signal increasing with increasing output speed; inverted modulator means providing an inverted modulator pressure signal decreasing with increasing torque demand; manually controlled valve means connected to said source and having a low drive line and a forward drive feed line and operative to connect said source in forward position to said forward feed line and in a low drive position to said forward and low drive feed lines; low first relay valve means connected to said low first feed line and said first drive device and having a low apply line connected to said low drive device, biasing means normally biasing said relay valve means to a first position connecting said low first feed line to said first drive device for establishing first drive and low signal means operated by pressure to move said relay valve means to a low position connecting said low first drive feed line to said low apply line and low drive device for establishing low drive and low shift signal valve means connected to said low drive line, said low apply line, said speed governor means, said modulator means, and said low signal means and having a valve element and a control element movably between open and closed positions in a bore having stop means preventing movement of said control element beyond said positions, said valve element in closed position blocking said low drive line and exhausting said low signal means and in open position connecting said low drive line to supply pressure from said low drive line to said low signal means, a low force spring biasing the valve element toward said open position and said control element, a high force spring biasing said control element toward said valve element and providing an excess differential biasing force engaging and moving both elements to closed position, said control element having an unbalanced area acted on by said inverted modulator pressure signal operative at and below a predetermined pressure at and above a predetermined low torque demand value permitting said excess differential force to move said engaged elements to closed position and on increase of said modulator pressure signal below said predetermined torque demand value overcoming said excess differential force to move said engaged elements to said open position, said governor pressure signal being connected to said bore between said elements in all positions and operative at speeds above a predetermined low speed to exert a force on said valve element to move it from open to closed position against said low force spring independent of torque demand and at speeds below said predetermined speed not affecting control by said torque demand pressure signal at said predetermined torque demand.

Claim 18

The invention defined in claim 12 and means to adjust the force of said high force spring to independently adjust said predetermined torque demand, and means to adjust the force of said low force spring to independently adjust said predetermined speed.

Claim 19

A transmission and control comprising: an input; an output; multiratio planetary gear means drive connected between said input and output having drive devices including selectively engageable low, first and second ratio drive engaging devices for establishing respectively low, first and secOnd ratio drives; a source of fluid under pressure; speed governor means connected to said output and said source providing a governor pressure signal increasing with increasing output speed; inverted modulator means providing an inverted modulator pressure signal decreasing with increasing torque demand; manual selector valve means connected to said source and having a low drive line and a forward drive feed line and operative to connect said source in a forward automatic position to said forward feed line and in a low drive position to said forward and low drive feed lines; first second automatic shift valve means connected to said second drive device, said speed governor means and said modulator means and having supply means supplied by said forward drive feed line and source and having a low first feed line and being upshifted and downshifted by said governor and modulator pressure signals and operative in a downshift position to connect said supply means to said low first feed line and in an upshift position to connect said supply means to said second drive device to engage second drive; low first relay valve means connected to said low first feed line and said first drive device and having a low apply line connected to said low drive device, low signal means operated by pressure to move said relay valve means from a first position connecting said low first feed line to said first drive device for establishing first drive to a low position connecting said low first drive feed line to said low apply line and low drive device for establishing low drive both only when said first second automatic shift valve means is in said downshift position and low shift signal valve means connected to said low drive line, said low apply line, said speed governor means, said modulator means, and said low signal means and having a valve element and a control element movably between open and closed positions in a bore having stop means preventing movement of said control element beyond said positions, said valve element in closed position blocking said low drive line and exhausting said low signal means and in open position connecting said low drive line to supply pressure from said low drive line to said low signal means, a low force spring biasing the valve element toward said open position and said control element, a high force spring biasing said control element toward said valve element and providing an excess differential biasing force engaging and moving both elements to closed position, said control element having an unbalanced area acted on by said inverted modulator pressure signal operative at and below a predetermined pressure at and above a predetermined low torque demand value permitting said excess differential force to move said engaged elements to closed position and on increase of said modulator pressure signal below said predetermined torque demand value overcoming said excess differential force to move said engaged elements to said open position, said governor pressure signal being connected to said bore between said elements in all positions and operative at speeds above a predetermined low speed to exert a force on said valve element to move it from open to closed position against said low force spring independent of torque demand and at speeds below said predetermined speed not affecting control by said torque demand pressure signal at said predetermined torque demand.

Claim 20

A transmission and control comprising: an input; an output; multiratio planetary gear means drive connected between said input and output having drive devices including selectively engageable low, first and second ratio drive engaging devices for establishing respectively low, first and secOnd ratio drives; a source of fluid under pressure; speed governor means connected to said output and said source providing a governor pressure signal increasing with increasing output speed; inverted modulator means providing an inverted modulator pressure signal decreasing with increasing torque demand; manual selector valve means connected to said source and having a low drive line and a forward drive feed line and operative to connect said source in a forward automatic position to said forward feed line and in a low drive position to said forward and low drive feed lines; first second automatic shift valve means connected to said second drive device, said speed governor means and said modulator means and having supply means supplied by said forward drive feed line and source and having a low first feed line and being upshifted and downshifted by said governor and modulator pressure signals and operative in a downshift position to connect said supply means to said low first feed line and in an upshift position to connect said supply means to said second drive device to engage second drive; low first relay valve means connected to said low first feed line and said first drive device and having a low apply line connected to said low drive device, low signal means operated by pressure to move said relay valve means from a first position connecting said low first feed line to said first drive device for establishing first drive to a low position connecting said low first drive feed line to said low apply line and low drive device for establishing low drive both only when said first second automatic shift valve means is in said downshift position and low shift signal valve means connected to said low drive line, said low apply line, said speed governor means, said modulator means, and said low signal means and having a valve element and a control element movably between open and closed positions in a bore having stop means preventing movement of said control element beyond said positions, said valve element in closed position blocking said low drive line and exhausting said low signal means and in open position connecting said low drive line to supply pressure from said low drive line to said low signal means, a low force spring biasing the valve element toward said open position and said control element, a high force spring biasing said control element toward said valve element and providing an excess differential biasing force engaging and moving both elements to closed position, said control element having an unbalanced area acted on by said inverted modulator pressure signal operative at and below a predetermined pressure at and above a predetermined low torque demand value permitting said excess differential force to move said engaged elements to closed position and on increase of said modulator pressure signal below said predetermined torque demand value overcoming said excess differential force to move said engaged elements to said open position, said governor pressure signal being connected to said bore between said elements in all positions and operative at speeds above a predetermined low speed to exert a force on said valve element to move it from open to closed position against said low force spring independent of torque demand and at speeds below said predetermined speed not affecting control by said torque demand pressure signal at said predetermined torque demand.

Claim 21

The invention defined in claim 14 and means to adjust the force of said high force spring to independently adjust said predetermined torque demand, and means to adjust the force of said low force spring to independently adjust said predetermined speed

Claim 22

A transmission and control comprising: an input; an output; multiratio planetary gear means drive connected between said input and output having a forward drive device, and selectively engageable low, first and second ratio drive engaging devices for establishing on engagement of said forward drive device respectively low, first and second rAtio drives; a source of fluid under pressure; speed governor means connected to said output and said source providing a governor pressure signal increasing with increasing output speed; inverted modulator means providing an inverted modulator pressure signal decreasing with increasing torque demand; manual selector valve means connected to said source and having a low drive line and a forward drive feed line connected to said forward device and operative to connect said source in a forward automatic position to said forward feed line and in a low drive position to said forward and low drive feed lines; first second automatic shift valve means connected to said source, said forward drive feed line, said second drive device, said speed governor means and said modulator means and having a low first feed line and being upshifted and downshifted by said governor and modulator pressure signals and operative in a downshift position to connect said source of said low first feed line and in an upshift position to connect said forward drive feed line to said second drive device to engage second drive; low first relay valve means connected to said low first feed line and said first drive device and having a low apply line connected to said low drive device, biasing means normally biasing said relay valve means to a first position connecting said low first feed line to said first drive device for establishing first drive and low signal means operated by pressure to move said relay valve means to a low position connecting said low first drive feed line to said low apply line and low drive device for establishing low drive both only when said first second automatic shift valve means is in said downshift position and low shift signal valve means connected to said low drive line, said low apply line, said speed governor means, said modulator means, and said low signal means and having a valve element and a control element movably between open and closed positions in a bore having stop means preventing movement of said control element beyond said positions, said valve element is closed position blocking said low drive line and exhausting said low signal means and in open position connecting said low drive line to supply pressure from said low drive line to said low signal means, a low force spring biasing the valve element toward said open position and said control element, a high force spring biasing said control element toward asid valve element and providing an excess differential biasing force engaging and moving both elements to closed position, said control element having an unbalanced area acted on by said inverted modulator pressure signal in a direction opposite to said high force spring operative at and below a predetermined pressure at and above a predetermined low torque demand value permitting said excess differential force to move said engaged elements to closed position and on increase of said modulator pressure signal below said predetermined torque demand value overcoming said excess differential force to move said engaged elements to said open position, said governor pressure signal being connected to said bore between said elements in all positions and operative at speeds above a predetermined low speed to exert a force on said valve element to move it from open to close position against said low force spring independent of torque demand and at speeds below said predetermined speed not affecting control by said torque demand pressure signal at said predetermined torque demand, means to adjust the force of said high force spring to independently adjust said predetermined torque demand, means to adjust the force of said low force spring to independently adjust said predetermined speed and having blocking means responsive to low apply pressure to hold said low shift signal valve means in open position.

Claim 23

A transmission and control comprising: an input; an output; multiratio planetary gear means drive connected between said input and output having a forward drive device, and selectively engageable low, first and second ratio drive engaging devices for establishing on engagement of said forward drive device respectively low, first and second rAtio drives; a source of fluid under pressure; speed governor means connected to said output and said source providing a governor pressure signal increasing with increasing output speed; inverted modulator means providing an inverted modulator pressure signal decreasing with increasing torque demand; manual selector valve means connected to said source and having a low drive line and a forward drive feed line connected to said forward device and operative to connect said source in a forward automatic position to said forward feed line and in a low drive position to said forward and low drive feed lines; first second automatic shift valve means connected to said source, said forward drive feed line, said second drive device, said speed governor means and said modulator means and having a low first feed line and being upshifted and downshifted by said governor and modulator pressure signals and operative in a downshift position to connect said source of said low first feed line and in an upshift position to connect said forward drive feed line to said second drive device to engage second drive; low first relay valve means connected to said low first feed line and said first drive device and having a low apply line connected to said low drive device, biasing means normally biasing said relay valve means to a first position connecting said low first feed line to said first drive device for establishing first drive and low signal means operated by pressure to move said relay valve means to a low position connecting said low first drive feed line to said low apply line and low drive device for establishing low drive both only when said first second automatic shift valve means is in said downshift position and low shift signal valve means connected to said low drive line, said low apply line, said speed governor means, said modulator means, and said low signal means and having a valve element and a control element movably between open and closed positions in a bore having stop means preventing movement of said control element beyond said positions, said valve element is closed position blocking said low drive line and exhausting said low signal means and in open position connecting said low drive line to supply pressure from said low drive line to said low signal means, a low force spring biasing the valve element toward said open position and said control element, a high force spring biasing said control element toward asid valve element and providing an excess differential biasing force engaging and moving both elements to closed position, said control element having an unbalanced area acted on by said inverted modulator pressure signal in a direction opposite to said high force spring operative at and below a predetermined pressure at and above a predetermined low torque demand value permitting said excess differential force to move said engaged elements to closed position and on increase of said modulator pressure signal below said predetermined torque demand value overcoming said excess differential force to move said engaged elements to said open position, said governor pressure signal being connected to said bore between said elements in all positions and operative at speeds above a predetermined low speed to exert a force on said valve element to move it from open to close position against said low force spring independent of torque demand and at speeds below said predetermined speed not affecting control by said torque demand pressure signal at said predetermined torque demand, means to adjust the force of said high force spring to independently adjust said predetermined torque demand, means to adjust the force of said low force spring to independently adjust said predetermined speed and having blocking means responsive to low apply pressure to hold said low shift signal valve means in open position.