Clutch Air Pressure Tests

CLUTCH AIR PRESSURE TESTS





Inoperative clutches can be located using a series of tests by substituting air pressure for fluid pressure using Air Pressure Test Plate 9741.


The clutches may be tested by applying air pressure to their respective passages. The valve body and oil filter must be removed and Air Pressure Test Plate 9741 installed. To make air pressure tests, proceed as follows:


NOTE: The compressed air supply must be free of all dirt and moisture. Use a pressure of 30 psi.

Remove oil pan and valve body, remove the oil filter oil pan and the oil filter.


OVERDRIVE CLUTCH


Apply air pressure to the overdrive clutch feed hole located on the test plate marked OD and watch for the push/pull piston to move forward. The piston should return to its starting position when the air pressure is removed.


REVERSE CLUTCH


Apply air pressure to the reverse clutch feed hole located on the test plate marked REV and watch for the push/pull piston to move rearward. The piston should return to its starting position when the air pressure is removed.


2/4 CLUTCH


Apply air pressure to the feed hole located on the test plate marked 2/4 clutch. Look in the area where the 2/4 piston contacts the first separator plate and watch carefully for the 2/4 piston to move rearward. The piston should return to its original position after the air pressure is removed.


LOW/REVERSE CLUTCH


Apply air pressure to the low/reverse clutch feed hole located on the test plate marked LR. Then, look in the area where the low/reverse piston contacts the first separator plate. Watch carefully for the piston to move forward. The piston should return to its original position after the air pressure is removed.


UNDERDRIVE CLUTCH


Because this clutch piston cannot be seen, its operation is checked by function. Air pressure is applied to the feed hole located on the test plate marked UD. This locks the output shaft. Use a piece of rubber hose wrapped around the input shaft and a pair of clamp-on pliers to turn the input shaft. Next apply air pressure to the underdrive clutch. The input shaft should not rotate with hand torque. Release the air pressure and confirm that the input shaft will rotate.


DIRECT CLUTCH


Apply air pressure to the feed hole located on the test plate marked DC, listen for an audible thud.


LOW CLUTCH


Apply air pressure to the feed hole located on the test plate marked LC, listen for an audible thud.