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AUTOMATIC TRANSMISSION 5A-69 MECHANICAL TESTS In Vehicle Transmission Checks Carry out the following tests before removing the transmission. ! See Checking Transmission Fluid Level, Section 7.2.1. ! Check that the transmission oil is not burnt (colour and smell are correct). ! Ensure that the transmission is not in limp home mode (LHM). ! Check that the battery terminals and the earth connections are not corroded or loose. ! Check the engine stall speed is within the handbook value. ! Check that the cooler flow is not restricted. ! Check that all electrical plug connections are tight. ! Carry out a road test to confirm the symptoms, if necessary. ! Inspect the oil, ensure that there are no metal or other contaminants in the oil pan. Diagnosing Oil Leaks Determine the source of oil leaks by firstly cleaning down the affected area, then driving the vehicle. Inspect the seals to confirm the source of the leak. ! To determine the source of a rear servo oil leak, raise the vehicle on a hoist, then carry out a reverse stall. ! To determine the source of a front servo leak, raise the vehicle on a hoist, then run the vehicle in second gear. Troubleshooting Charts The troubleshooting charts are set out as follows: ! Table 6.2.1 Drive Faults, ! Table 6.2.2 Faulty Shift Patterns. ! Table 6.2.3 Shift Quality Faults. ! Table 6.2.4 After Teardown Faults. Table 6.2.1 - Drive Faults Action Check the fluid level. Top up as necessary. Inspect and clean C1/C2 feed. Reinstall/renew the ‘z’ link. Remove, clean and re-install the PRV. Inspect and replace as necessary. Inspect and replace as necessary. Inspect and replace as necessary. Check servo adjustment or replace rear band as necessary. Check for failure in C3, C3 hub or C1/C2 cylin- der. Repair as necessary. Inspect and clean PRV. Inspect and replace pump gears as necessary. Inspect and repair as necessary. Possible Cause Insufficient auto transmission fluid. Blocked feed in C1/C2 cylinder. ‘Z’ link displaced. Primal regulator valve (PRV) jammed open. Overdrive shaft or input shaft seal rings failed. 3-4 or 1-2 one way clutch (OWC) installed backwards or failed. C2 piston broken or cracked. Rear band or servo faulty. Failure in C3, C3 hub or C1/C2 cylinder. Jammed primary regulator valve (PRV). Damaged/broken pump gears. Dislodged output shaft snap ring. Symptom No Drive in D No Drive in Reverse No engine braking in Manual 1 Engine braking in Manual 1 is OK No drive in Drive and Reverse |