Clutch Air Pressure Tests

CLUTCH AIR PRESSURE TESTS




Figure 1 Air Pressure Test Plate







Inoperative clutches can be located using a series of tests by substituting air pressure for fluid pressure using Air Pressure Test Plate 6056 (1) (Figure 1).





Figure 2 Testing Reverse Clutch







The clutches may be tested by applying air pressure (2) (Figure 2) to their respective passages. The valve body must be removed and Air Pressure Test Plate 6056 (1) 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.


OVERDRIVE CLUTCH


Apply air pressure to the overdrive clutch apply passage 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 apply passage 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 2/4 clutch retainer. 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 (rear of case, between 2 bolt holes). 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 low/reverse and the 2/4 clutches. 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.