Road Test

A750F AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: ROAD TEST

ROAD TEST

1. PROBLEM SYMPTOM CONFIRMATION
(a) Based on the result of the customer problem analysis, try to reproduce the symptoms. If the problem is that the transmission does not shift up, shift down, or the shift point is too high or too low, conduct the following road test while referring to the automatic shift schedule and simulate the problem symptoms.
2. ROAD TEST
NOTE: Perform the test at the normal operating ATF (Automatic Transmission Fluid) temperature: 50° to 80°C (122° to 176°F).

(a) D position test:
Shift into the D position, fully depress the accelerator pedal and check the following points.
(1) Check up-shift operation.
Check that 1 -> 2, 2 -> 3, 3 -> 4 and 4 -> 5th up-shifts take place, and that the shift points conform to the automatic shift schedule Pressure, Vacuum and Temperature Specifications.
HINT: 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 (116.6°F) or less and vehicle speed is 30.4 mph (49 km/h) or less.
5th Gear Lock-up Prohibition Control
- Brake pedal is depressed.
- Accelerator pedal is released.
- Engine coolant temperature is 60°C (140°F) or less.
(2) Check for shift shock and slippage
Check for shock and slippage at the 1 -> 2, 2 -> 3, 3 -> 4 and 4 -> 5th up-shifts.
(3) Check for abnormal noise and vibration.
Check for abnormal noise and vibration when up-shifting from 1 -> 2, 2 -> 3, 3 -> 4 and 4 -> 5 while driving with the shift lever in the D position, and check 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.
(4) Check kick-down operation.
Check vehicle speeds when the 2 -> 1, 3 -> 2, 4 -> 3, and 5 -> 4 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 Pressure, Vacuum and Temperature Specifications.
(5) Check for abnormal shock and slippage at kick-down.
(6) Check the lock-up mechanism.

- Drive in the D position (5th gear), at a steady speed (lock-up ON).
- Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.
HINT: If there is a sudden increase in engine speed, there is no lock-up.

(b) 4 position test:
Shift into the 4 position, fully depress the accelerator pedal and check the following points.
(1) Check up-shift operation.
Check that the 1 -> 2, 2 -> 3 and 3 -> 4 up-shifts take place and that the shift points conform to the automatic shift schedule Pressure, Vacuum and Temperature Specifications.
HINT:
- There is no 5th up-shift in the 4 position.
- 4th Gear Lock-up Prohibition Control
- Brake pedal is depressed.
- Accelerator pedal is released.
- Engine coolant temperature is 60°C (140°F) or less.
(2) Check engine braking.
While driving in the 4 position and 4th gear, release the accelerator pedal and check the engine braking effect.
(3) Check for abnormal noises during acceleration and deceleration, and for shock at up-shift and down-shift.
(4) Check the lock-up mechanism.

- Drive in the 4 position and 4th gear, at a steady speed (lock-up ON).
- Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.
HINT: If there is a sudden increase in engine speed, there is no lock-up.

(c) 3 position test:
Shift into the 3 position, fully depress the accelerator pedal and check the following points.
(1) Check up-shift operation.
Check that the 1 -> 2 and 2 -> 3 up-shifts take place and that the shift points conform to the automatic shift schedule Pressure, Vacuum and Temperature Specifications.
HINT: There is no 4th up-shift and lock-up in the 3 position.
(2) Check engine braking.
While running in the 3 position and 3rd gear, release the accelerator pedal and check the engine braking effect.
(3) Check for abnormal noises during acceleration and deceleration, and for shock at up-shift and down-shift.
(d) 2 position test:
Shift into the 2 position, fully depress the accelerator pedal and check the following points.
(1) Check up-shift operation.
Check that the 1 -> 2 up-shift takes place and that the shift point conforms to the automatic shift schedule Pressure, Vacuum and Temperature Specifications.
HINT: There is no 3rd up-shift and lock-up in the 2 position.
(2) Check engine braking.
While running in the 2 position and 2nd gear, release the accelerator pedal and check the engine braking effect.
(3) Check for abnormal noises during acceleration and deceleration, and for shock at up-shift and down-shift.
(e) L position test:
Shift into the L position and fully depress the accelerator pedal and check the following points.
(1) Check no up-shift.
While running in the L position, check that there is no up-shift to 2nd gear.
(2) Check engine braking.
While running in the L position, release the accelerator pedal and check the engine braking effect.
(3) Check for abnormal noises during acceleration and deceleration.
(f) 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 obstructions.

(g) 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.