GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Kodiak C-Series (Conventional) C6/C7/C8 🢒 Transmission/Transaxle 🢒 Manual Transmission - ZF S6-650 🢒 Transmission Clunk on Acceleration or Deceleration

Diagnostic Aids

All manual transmissions have gear play that may cause a clunk. If the transmission is suspected of causing the clunk, compare it with a similar vehicle. An internal clunk in the transmission is usually caused by wear between two components, or from improper assembly, which would also cause other symptoms.

Step

Action

Yes

No

DEFINITION: A clunk is heard and/or felt on acceleration or deceleration.

1

Did you review the Symptoms - Manual Transmission and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Manual Transmission

2

Inspect the engine mounts for being loose or damaged. Refer to Engine Mount Inspection in Engine Mechanical - 6.6L or Engine Mount Inspection in Engine Mechanical - 8.1L.

Did you find and repair the condition?

Go to Step 7

Go to Step 3

3

Inspect the transmission mounts for being loose or damaged. Refer to Transmission Mount Replacement .

Did you find and repair the condition?

Go to Step 7

Go to Step 4

4

Notice: Refer to Fastener Notice in the Preface section.

Inspect the transmission to engine fasteners for being loose or missing. Refer to Fastener Tightening Specifications .

Did you find and repair the condition?

Go to Step 7

Go to Step 5

5

Inspect the driveline for causing the clunk. Refer to Propeller Shaft Diagnosis in Propeller Shaft.

Did you find and repair the condition?

Go to Step 7

Go to Step 6

6
  1. Remove the transmission. Refer to Transmission Replacement .
  2. Disassemble the transmission. Refer to Transmission Disassemble .
  3. Inspect the following transmission components that may be causing the clunk:
    4. • The mainshaft bearing preload
    • The countershaft bearing preload
    • Worn speed gear teeth
    • Worn countershaft gear teeth
    • Worn synchronizer sleeve to hub
    • Worn thrust washers and thrust surfaces on the speed gears or mainshaft

Did you find and repair the condition?

Go to Step 7

Go to Diagnostic Aids

7

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 1