GM Service Manual Online
For 1990-2009 cars only

Condition

Action

DEFINITION: Harsh shift felt when shifting from park to neutral into reverse

Fluid level low and/or burnt

    • Perform Transmission Fluid Check .
    • If low inspect for fluid leak, repair as necessary.
    • Inspect transmission oil cooler system for restricted or kinked lines.
    • Flush system. Refer to Transmission Fluid Cooler Flushing and Flow Test .

Fluid is contaminated with water or engine coolant

If contaminated with engine coolant replace transmission.

Unit filled with wrong type of fluid

Drain fluid and fill with proper type of fluid.

Input speed sensor (76)

    • Perform electrical function test on the input speed sensor (76).
    • Replace the input speed sensor (76) if fails electrical function test.

Park/neutral position switch (72)

    • Inspect park/neutral switch (72) for proper alignment.
    • Align the park/neutral switch (72) if not properly aligned.
    • Perform function test on the park/neutral position switch (72).
    • Replace the park/neutral position switch (72) if faulty.

Engine or transmission mounts

    • Inspect the engine mounts and the transmission mounts for wear or loose mounting fasteners.
    • Replace any faulty engine or transmission mounts or loose fasteners.

Engine malfunction

    • Ensure engine is operating properly.
    • Repair engine to operate properly.

Drive shafts

    • Inspect the drive shafts for worn components.
    • Repair the drive shaft if worn.

Suspension system

    • Inspect suspension components.
    • Replace faulty suspension components.

Transmission oil temperature sensor (32)

    • Perform function test on the transmission oil temperature sensor (32).
    • Replace the automatic transmission wiring harness assembly (78).

Line pressure control solenoid valve assembly (SLT) (312)

    • Perform electrical function checks on the line pressure control solenoid valve assembly circuit.
    • Perform electrical function check on the line pressure control solenoid valve assembly (312).
    • Replace valve body assembly (39) if line pressure control solenoid valve assembly is faulty.

Transmission control module (TCM)

    • Perform function test on the TCM.
    • Replace TCM if fails function test.

Valve body (39)

Replace valve body (39).

Internal transmission parts

    • Disassemble the transmission and inspect for the following:
       - Missing retaining rings
       - Worn or broken thrust needle bearings and thrust washers
       - Differential assembly backlash
       - Worn drive and driven gears
       - Worn planetary gear assemblies
    • Replace the transmission if any faulty parts.