powershift trans and auto trans shifting and control

Question 1

what are the three control circuits

Answer 1

clutch application - torque converter and charging -transmission lubrication

Question 2

what is the purpose of the priority valve in the transmission control circuit

Answer 2

to allow the shift selector valve to receive working pressure before sending oil downstream

Question 3

what is the purpose of the torque inlet relief valve

Answer 3

to dump oil back to the trans sump during cold start up

Question 4

what is the purpose of the lube pressure release valve

Answer 4

to dump oil back to the trans sump if lubricating pressure for the trans gears is exceeded

Question 5

when towing a unit with a powershift transmission care must be taken because

Answer 5

when towing the unit the charge pump will not be lubricating the gears as they are turning

Question 6

what must you do before towing a unit with power shift transmission

Answer 6

elevate the drive wheels - remove the drive axles - remove the drive line to prevent transmission rotation

Question 7

speed selector spool

Answer 7

directs oil from the transmission charging pump to the speed clutches in the planetary transmission

Question 8

modulation relief valve

Answer 8

controls the maximum clutch application pressure

Question 9

load piston

Answer 9

controls the rate of pressure rise in the clutch pistons

Question 10

what does clutch modulation do for the system

Answer 10

prevents shift shock and excessive slippage

Question 11

what will send oil to the direction clutches in a planetary

Answer 11

direction selector spool

Question 12

what will happen if coolant is allowed to enter the transmission with composite clutches

Answer 12

they will be destroyed

Question 13

what is function on an automatic transmission will provide upshifts and down shifts in refrence to ground speed

Answer 13

governor circuit

Question 14

what is governor pressure also used for

Answer 14

to apply and release the lock up clutch

Question 15

what are the four methods to control shift dampening

Answer 15

orifice - modulation - trimmer - accumulator

Question 16

where is an orifice used to control clutch dampening

Answer 16

on the release circuit

Question 17

a trimmer valve is used in

Answer 17

the application circuit of the clutch

Question 18

the three electronic transmission shift control systems are

Answer 18

input components - processing components - output components

Question 19

when T/S a electronically controlled transmission one of the first checks to preform would be

Answer 19

power supply

Question 20

the function of the modulator circuit is to

Answer 20

provide a signal pressure that is proportional to the position of the engine throttle - used to delay transmission shift points during wide open throttle operation

Question 21

oil flow for the transmission control system operation is supplied by

Answer 21

a charging pump that is driven at engine speed

Question 22

output devices that are responsible for causing speed and direction changes are

Answer 22

speed sensors

Question 23

the hydraulic governor in an automatic transmission operates by balancing the centrifugal force of the governor flyweights against

Answer 23

governor pressure

Question 24

before oil travels into the transmission lubrication circuit it will be

Answer 24

cooled and filtered

Question 25

the function of the governor circuit in an automatic transmission is to

Answer 25

provide a hydraulic signal that is proportional to engine ground speed

Question 26

if a clutch is released much more quickly than the next clutch to be applied during a shift the result is

Answer 26

a flare up of engine rpm and momentary free wheeling of machine until the next clutch is fully applied

Question 27

momentary engine lugging and slowing of machine speed during shift indicates

Answer 27

releasing clutch that has not fully released before next clutch is applied

Question 28

what are four functions of the ECU in an electronically controlled shift system

Answer 28

control upshifts and downshifts - control clutch modulation - provide diagnostic information - provide a warning to the operator when a malfunction has occurred