Road Test - Performance Evaluation

DESCRIPTION
The following tests, Shift Point Road Test and Torque Converter Clutch Operation Test, provide diagnostic information on transmission shift controls and torque converter operation.

SHIFT POINT ROAD TEST
This test verifies that the shift control system is operating properly.
1. Bring engine and transaxle up to normal operating temperature.
2. Operate vehicle with transaxle range selector lever in D position.
3. Apply minimum throttle and observe speeds at which upshift occurs and torque converter engages.

NOTE: Shift speed ranges are approximate for all applications.

Test: mph
LT 1-2*: 31/14 km/h (19/9 mph)
LT 2-3*: 48/32 km/h (30/20 mph)
LT 3-4*: 72/56 km/h (45/35 mph)
CT 4-3: 43/27 km/h (27/17 mph)
CT 3-2: N/A
CT 3-1: 24/8 km/h (15/5 mph)
CT 2-1: 24/8 km/h (15/5 mph)
MAN 2-1: 60/43 km/h (37/27 mph)
PT 1-2**: 35/19 km/h (22/12 mph)
PT 2-3**: 72/48 km/h (45/30 mph)
PT 3-4**: 113/88 km/h (70/55 mph)
WOT 1-2: 68/48 km/h (40/30 mph)
WOT 2-3: 126/100 km/h (72/62 mph)
WOT 3-4: 172/156 km/h (107/97 mph)
CFDR3.77

* Perform light-throttle shifts at approximately 13% throttle opening.
** Perform part-throttle shifts at approximately 30% throttle opening.

4. With the vehicle in D (fourth gear), depress the Transmission Control Switch. The transaxle should downshift to third gear. Remove foot from accelerator pedal; engine braking should occur. Torque converter clutch should disengage and then reapply.
5. Depress accelerator pedal to floor (WOT). Transaxle should shift from third to second gear, or third to first depending on vehicle speed.
6. With vehicle in D range above 80 km/h (50 mph) and less than half throttle, move the transaxle range selector lever from D range to manual 2 range and remove foot from accelerator pedal. The transaxle should immediately downshift into second gear. With the vehicle remaining in manual 2 range, move the transaxle range selector lever into manual 1 range and release the accelerator pedal. The transaxle should downshift into first gear at speeds BELOW 48-56 km/h (28-32 mph).
7. If transaxle fails to upshift/downshift or torque converter clutch does not apply and release, other possible causes will be found in Diagnosis By Symptom.

TORQUE CONVERTER CLUTCH OPERATION TESTS
This test verifies that the torque converter clutch control system and the torque converter are operating properly. Perform the test as follows:
1. Perform On-Board Diagnostic Quick Tests in Powertrain Management. Follow appropriate pinpoint test or procedure for diagnosis.
2. Connect a tachometer to the engine.
3. Bring engine to normal operating temperature by driving the vehicle at highway speeds for approximately 15 minutes in D position.
4. After normal operating temperatures are reached, maintain a constant vehicle speed of about 80 km/h (50 mph) and tap the brake pedal with the left foot.
5. Engine rpm should increase when the brake pedal is tapped, and decrease about five seconds after the brake pedal is released. If this does not occur, go to Torque Converter Operation Concerns in the Diagnosis by Symptom charts.
6. If the vehicle stalls in D at idle with the vehicle at a stop, move the transaxle range selector lever to the manual 1 position. If the vehicle stalls, the cause may be the converter control valve in the pump. Service as required. If the vehicle does not stall in manual 1, go to Pinpoint Test C. Pinpoint Tests
7. Perform visual inspection.
8. After a road test, with the vehicle warm and before disturbing any connectors, perform the Quick Test using Rotunda New Generation Star (NGS) Tester 007-00500 or equivalent.
9. Refer to all technical service bulletins which pertain to the transaxle concern and follow the procedures.