LINER 3384347 - Caterpillar

Introduction
This procedure should be performed if the machine will not operate in THIRD speed FORWARD or REVERSE but the machine will operate in all other speed ranges. Step 1. Check gear lock out.a. Check gear high speed lockout limit (sub mode 20 and 21) to verify which gears are available.Reference: Refer to Power Train Electronic Control System, SENR8367, "Submode 20 - Set Forward High Speed Lockout" and ""Submode 21 - Set Reverse High Speed Lockout" for additional information. Expected Result: Third gear is not available. Results:* YES - The transmission will not operate in third because that gear is locked out. STOP.* NO - Proceed to Step 2. Step 2. Operate machine.a. Start and run the engine.b. Shift the transmission into third gear forward.c. Attempt to operate the machine. Expected Result: The engine speed decreases. Results:* OK - Proceed to Step 3.* NOT OK - Proceed to Step 4. Step 3. Check brake pressure.a. With the engine at low idle, the transmission in neutral and the parking brake disengaged, check the brake pressure at the brake control valve.
Figure 1: Steering and Brake Control Valve (11)
(F) Steering clutch (left). (G) Brake (left). (H) Brake (right). (J) Steering clutch (right). Expected Result: The pressure should be 2750 150 kPa (400 25 psi). Results:* OK - Proceed to Step 5.* NOT OK - Proceed to Step 6. Step 4. Check pressure.a. Start and run the engine at high idle.b. Disengage the parking brake.c. Shift the transmission into Third gear Forward.d. Wait at least 5 seconds after shifting the transmission and then measure the pressure at clutch 3 (14C).
Figure 2: Transmission Controls
(14) Modulating valve. (14A) Clutch one (modulating valve). (14B) Clutch two (modulating valve). (14C) Clutch three (modulating valve). (14D) Clutch four (modulating valve). (14E) Clutch five (modulating valve). Expected Result: The pressure is within specifications (less than 2690 kPa (390 psi)). Results:* OK - Preform the following tests for No. 3 clutch only. Proceed to Step 10.* NOT OK - Proceed to Step 7. Step 5. Perform Transmission Clutch Engaged And Will Not Release. Results:* REPAIRED, OK - STOP.* OK - STOP. Step 6. Perform Brkenor: Brake Engaged And Will Not Release. Results:* REPAIRED, OK - STOP.* OK - STOP. Step 7. Interchange valves.a. Interchange the transmission modulating valve for clutch 3 (14C) with the transmission modulating valve for clutch 5 (14E).b. Verify whether the problem "follows" the valve.See Figure 2: Transmission Controls Results:* FOLLOWS VALVE - Proceed to Step 8.* PROBLEM REMAINS - Perform the following tests for No. 3 clutch only. Proceed to Step 10.* PROBLEM GOES AWAY - Proceed to Step 9. Step 8. Inspect valve.a. Disassemble and inspect the suspect transmission modulating valve.b. Repair as required.c. Return valve to its original position.d. Check operation of machine for original complaint. Expected Result: The original complaint is resolved. Results:* OK - Calibrate the transmission modulating valve using the procedure in SENR8367 "Power Train Electronic Control System". Reference: Refer to Power Train Electronic Control System, SENR8367, "Submode 31