Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Road Test
- PROBLEM SYMPTOM CONFIRMATION
- Based on the result of the customer problem analysis, try to reproduce the symptoms. If the problem is that the transaxle does not shift up or down, or the shift point is too high or too low, conduct the following road test referring to the automatic shift schedule and attempt to duplicate the problem symptoms.
- ROAD TEST NOTE: Perform the test at the ATF (Automatic Transmission Fluid) temperature 50 to 80°C (122 to 176°F) in the normal operation.
- D position test:
Shift into the D position, fully depress the accelerator pedal and check the following:
- Check up-shift operation.
Check that 1st to 2nd, 2nd to 3rd, 3rd to 4th, 4th to 5th and 5th to 6th up-shifts take place, and that the shift points conform to the automatic shift schedule (See U660E AUTOMATIC TRANSAXLE ).
HINT:
6th Gear Up-shift Prohibition Control
- Engine coolant temperature is 60°C (140°F) or less and vehicle speed is 50 mph (80 km/h) or less.
5th Gear Up-shift Prohibition Control
- Engine coolant temperature is 55°C (131 °F) or less and vehicle speed is 32 mph (51 km/h) or less.
4th Gear Up-shift Prohibition Control
- Engine coolant temperature is 47°C (117°F) or less and vehicle speed is 31 mph (49 km/h) or less.
Lock-up Prohibition Control
- Brake pedal is depressed.
- Accelerator pedal is released.
- Engine coolant temperature is 60°C (140°F) or less.
- Check for shift shock and slip.
Check for shock and slip at the 1st to 2nd, 2nd to 3rd, 3rd to 4th, 4th to 5th and 5th to 6th up-shifts.
- Check for abnormal noise and vibration.
Check for abnormal noise and vibration when up-shifting from 1st to 2nd, 2nd to 3rd, 3rd to 4th, 4th to 5th and 5th to 6th white driving with the shift lever in the D position, and also while driving in the lock-up condition.
HINT:
The check for the cause of abnormal noise and vibration must be done thoroughly as it could also be due to loss of balance in the differential, torque converter clutch, etc.
- Check kick-down operation.
Check vehicle speeds when the 6th to 5th, 5th to 4th, 5th to 3rd, 3rd to 2nd, and 2nd to 1st kick-downs take place while driving with the shift lever in the D position. Confirm that each speed is within the applicable vehicle speed range indicated in the automatic shift schedule (See U660E AUTOMATIC TRANSAXLE ).
- Check for abnormal shock and slip at kick-down.
- Check the lock-up mechanism.
- Drive the vehicle with the shift lever in the D position (2nd, 3rd, 4th, 5th or 6th gear) at a steady speed (lock-up ON).
- Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.
HINT:
- There is no lock-up function in the 1st gear.
- If there is a jump in engine speed, this indicates that lock-up is not operating.
- Check up-shift operation.
- S position test
Shift to the S position, depress the accelerator pedal and check the following:
- Check shift operation.
- With the shift lever in the S position (while the vehicle is stopped), shift into the "+" position to check that the shift position on the combination meter changes as follows: 1 to 2, 2 to 3, 3 to 4, 4 to 5 and 5 to 6.
- While driving in the 5 (S) position and 5th gear (at a vehicle speed of approximately 34 to 40 mph (55 to 65 km/h)), shift into the"-" position and check if the 4th gear down-shift occurs and proper engine braking occurs.
- While driving in the 4 (S) position and 4th gear (at a vehicle speed of approximately 19 to 25 mph (30 to 40 km/h)), shift into the "-" position and check if the 3rd gear down-shift occurs and proper engine braking occurs.
- While driving in the 3 (S) position and 3rd gear (at a vehicle speed of approximately 12 to 19 mph (20 to 30 km/h)), shift into the "-" position and check if the 2nd gear down-shift occurs and proper engine braking occurs.
- While driving in the 2 (S) position and 2nd gear (at a vehicle speed of approximately 6 to 12 mph (10 to 20 km/h)), shift into the"-" position and check if the 1st gear down-shift occurs and proper engine braking occurs.
HINT:
Manual shift (S position) is prohibited under either of the following conditions:
- Down-shifting may cause engine overrun.
- The driver continuously down-shifts. (Downshifting to 1st gear may not be performed.)
- Check shift operation.
- R position test:
Shift into the R position, lightly depress the accelerator pedal, and check that the vehicle moves backward without any abnormal noise or vibration.
CAUTION: Before conducting this test ensure that the test, area is free from people and obstruction. - P position test:
Stop the vehicle on a grade (more than 5°) and after shifting into the P position, release the parking brake. Then, check that the parking lock pawl holds the vehicle in place.
- D position test:
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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