GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC K Sierra - 4WD 🢒 Transmission/Transaxle 🢒 Manual Transmission - NV 4500 🢒 Transmission Jumps Out of Gear

Diagnostic Aids

The manual transmission can have a number of problems to make it jump out of gear. Some of the most common ones are misalignment of the transmission to engine, the clutch housing loose, or misalignment. The transmission should also be checked for worn or damaged input bushing to flywheel or worn or damaged input and output shaft bearings. An bent input shaft could also be the result of the transmission jumping out of gear. When going into the internal part of the transmission also check for worn detent springs, synchronizers, worn teeth on the gears or even worn thrust washers. When doing inspections of the manual transmission you should inspect all internal parts for worn or damaged parts. You should also perform a static shift and dynamic shift test.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This step is inspecting for the position of the shift control closeout boot.

    2.

  2. This step checks for worn or damaged transmission or engine mounts.

    3.

  3. This step is checking for worn or damaged internal parts.

Step

Action

Yes

No

DEFINITION: Gear disengagement occurs during normal operation.

1

Did you review the manual transmission symptom operations and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Manual Transmission

2

  1. Inspect the transmission shift tower.
  2. Perform a static shift test.

Can you shift into all gear positions?

Go to Step 4

Go to Step 3

3

Reposition or replace the shift tower. Refer to Shift Tower Replacement .

Did you find and repair the condition?

Go to Step 11

Go to Step 4

4
  1. Inspect the transmission shift lever.
  2. Perform a dynamic shift test.

Can you shift into all gear positions?

Go to Step 6

Go to Step 5

5

Replace the transmission shift lever. Refer to Shift Lever Replacement .

Did you find and repair the condition?

Go to Step 11

Go to Step 6

6

Inspect the engine and/or transmission mounts.

Did you find and repair the condition?

Go to Step 11

Go to Step 7

7

Inspect the clutch housing for loose bolts or misalignment.

Are there any loose bolts or misalignment?

Go to Step 8

Go to Step 9

8

Tighten any loose housing bolts and/or align the housing . Refer to Fastener Tightening Specifications in Clutch.

Did you find and repair the condition?

System OK

Go to Step 11

9

  1. Remove the transmission. Refer to Transmission Replacement .
  2. Disassemble and inspect the following internal components for wear or damage:
    3. • Gearshift
    • Transmission gears
    • Bearings

Is there any worn or damaged components?

Go to Step 10

System OK

10
  1. Replace any worn or damaged components. Refer to Transmission/Transaxle/Transfer Case Unit Repair Manual.
  2. Install the transmission. Refer to Transmission Replacement .

Did you find and repair the condition?

Go to Step 11

Go to Diagnostic Aids

11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 1