||Place the shift lever in neutral. Check for constant air leakage at the shift knob, slave valve, and transmission case breather when both low and high range have been selected.
||Constant air leak is detected.
||Go to the other corresponding symptom first. See beginning of Air System Troubleshooting section.
|No constant leak is detected.
||Go to Step 2
||Place shift lever in neutral. Move range selector down to low range position. At the transmission rear, disconnect the 1/4″ rubber air line from the range cylinder high range supply port. Check for air flow from the cylinder high range port.
||Air flows from the high range port.
||Remove range cylinder cover and repair leaking range piston or piston seal. After repair, check for proper range operation.
|No air flow from high range port.
||Go to Step 3
||Check for air flow from the disconnected air line.
||Air flows from disconnected air line.
||Go to step 6.
|No air flows from disconnected air line.
||Go to Step 4
||Install a 100 PSI air gauge in the disconnected air line end. With the shift lever in neutral, move the range selector down to select high range. Observe the gauge
||The gauge read 0 PSI.
||Go to step 6.
|The gauge reads pressure but is lower than 58 PSI or higher than 63 PSI.
||Replace the filter/regulator and check for proper range operation.
|The gauge reads between 58 – 63 PSI.
||Go to Step 5
||Confirm that shift lever is still in neutral. Have an assistant move the range selector up and down between low and high range. Does the pressure measured at the gauge respond rapidly when going from high to low?
||Pressure rapidly changes between 58-63 PSI and 0 at the gauge.
||Air system appears to be operating satisfactory. Go to step 10.
|Pressure does not change rapidly at gauge.
||1. Check for a plugged or dirty filter in the filter/regulator assembly.
|2. Check for a pinched or obstructed 1/4″ rubber air line between the filter/regulator and slave valve.
|3. Check for a pinched or obstructed 1/4″ rubber air line between the slave valve and the test gauge.
|rubber air line between the slave valve and the test gauge.
|5. If all are satisfactory, go to step 6.
||Place shift lever in neutral. At the shift knob, move the range selection lever up to select high range. At the slave valve, remove the air line from the “P” port. (should be a black line). Check for air flow from the disconnected line.
||Air flows from the disconnected line.
||1. Confirm that the air lines are connected to the correct ports at the shift knob.
|2. If the lines are correct, replace the shift knob.
|No air flow from the disconnected line.
||Go to Step 7
||Check for air coming out of the slave valve “P” port.
||Air flows from this port
||Replace the slave valve.
|No air flows from this port
||Go to step 8
||Place the shift lever in neutral. Install a 100 PSI pressure gauge in line with the “P” line. Move the range selector back and forth from low to high range. The gauge should show rapid pressure change.
||The gauge responds slowly.
||1. Check for a restricted line between the shift knob and slave valve.
|2.Check for a restricted exhaust port on the shift knob.
|3. Check for a plugged or dirty filter in the filter / regulator assembly.
|4. Check for a pinched or obstructed 1/4″ rubber air line between the filter/regulator and slave valve.
|5. Check for a pinched or obstructed air line between the slave valve and the “S” port on the shift knob.
|6. If all are good, replace the shift knob.
|The gauge rapidly moves between 58-63 PSI and 0 PSI.
||Go to step 9.
||If possible, leave air lines attached to slave valve. Unbolt the slave valve from transmission side. Check for free movement of the plunger pin protruding from the case under the slave valve. The pin should extract when the transmission is shifted into gear and retract when shifted into neutral. If desired, the slave valve can be actuated and tested while unbolted from the transmission case. The air lines, of course, must remain attached.
||Actuating plunger pin does not move freely
||1. Remove actuating plunger pin and check for damage.
|2. Check for missing or broken spring.
|Actuating plunger pin moves freely.
||Repair or replace slave valve and check for proper range operation.
||If air system has been tested and found to operate satisfactory, the auxiliary section must be removed to inspect for mechanical problem. Remove auxiliary section and inspect for:
•Binding of range yoke bar or piston
•Damaged or defective range yoke
•Damaged or defective range synchronizer
•Cracked countershaft weld resulting in
gear turning on shaft
•Damaged or defective range sliding clutch
•Auxiliary section gearing out of time