Diesel Data: Automotive Repair

Shift Point Road Test

Shift Point Road Test
This test verifies that the shift control system is operating correctly.
1. Bring the engine and transmission up to normal operating temperature.
2. Operate the vehicle with the selector lever in the D position.
3. Apply minimum throttle and observe the speeds at which upshift occurs and the torque converter engages. Refer to the following Shift Speeds chart
4. Stop the vehicle. Select the D position and cancel overdrive by pressing the transmission control (TC) switch. Repeat Step 3. The transmission will make all upshifts except 4-5 and the torque converter clutch (TCC) should apply above 46 km/h (27 mph).
5. Press the accelerator pedal to the floor, wide open throttle (WOT). The transmission should shift from 3rd to 2nd, or 3rd to 1st, depending on vehicle speed, and the TCC should release.
6. With the vehicle speed above 48 km/h (30 mph), move the transmission range selector lever from D position to manual 1st position and release the accelerator pedal. The transmission should immediately downshift to 3rd gear. When vehicle speed drops below 32 km/h (20 mph), the transmission should downshift into 1st gear.
7. If transmission fails to upshift/downshift or the TCC does not apply/release, refer to Diagnosis By Symptom for possible causes. Diagnosis By Symptom

Shift Speeds - 4.0L Engine

Shift Speeds - 4.0L Engine:





Shift Speeds - 4.6L Engine

Shift Speeds - 4.6L Engine: