GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2001 🢒 GMC K Sierra - 4WD 🢒 Transmission/Transaxle 🢒 Manual Transmission - NV 4500 🢒 Transmission Gear Clash When Shifting Gears

Diagnostic Aids

Gear clash is a grinding noise that is made when shifting gears. You should also perform a static shift and dynamic shift test. If the transmission develops gear clash, first check the clutch adjustment or faulty clutch condition. A clutch that drags or does not fully engage is the most common cause of gear clash. If the clutch is at fault , the clash should occur in every gear. If the clutch is all right, or the clash does not occur in all gears, check for worn or damaged synchronizers, including the sleeves, hubs and the blocking rings. Also check for loose mounting bolts or misalignment.

Test Description

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

  1. This step checks for proper clutch operations.

  2. This step checks for air the hydraulic clutch system.

  3. This step checks for worn pilot hearing.

Step

Action

Yes

No

DEFINITION: The transmission gears clash when shifting from one gear into another gear.

1

Did you review the manual transmission symptoms and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Manual Transmission

2

Inspect for proper clutch operation. Refer to Symptoms - Clutch in Clutch.

Does the clutch operate properly?

Go to Step 7

Go to Step 3

3

Verify that the clutch is releasing properly. Refer to Hydraulic Clutch Description in Clutch.

Is the clutch releasing properly?

Go to Step 5

Go to Step 4

4

Repair the clutch system. Refer to Clutch Assembly Replacement in Clutch.

Did you find and repair the condition?

Go to Step 16

Go to Step 5

5

Test for air in the clutch hydraulic system.

Is there air in the hydraulic system?

Go to Step 6

Go to Step 7

6

Bleed the clutch hydraulic system. Refer to Hydraulic Clutch Bleeding in Clutch.

Did you find and repair the condition?

Go to Step 16

Go to Step 7

7

Inspect the transmission shift control for wear.

Is the transmission control worn?

Go to Step 8

Go to Step 9

8

Replace the transmission shift tower. Refer to Shift Tower Replacement .

Did you find and repair the condition?

Go to Step 16

Go to Step 9

9

Inspect the transmission fluid level. Refer to Fluid Replacement .

Did you find and repair the condition?

Go to Step 16

Go to Step 10

10

Inspect for the correct type transmission fluid.

Is the correct type transmission fluid being used?

Go to Step 12

Go to Step 11

11

Drain and refill the transmission. Refer to Fluid Replacement .

Did you find and repair the condition?

Go to Step 16

Go to Step 12

12

Inspect the clutch pilot bearing for binding.

Is the pilot bearing binding?

Go to Step 13

Go to Step 14

13
  1. Replace the clutch pilot bearing. Refer to Clutch Pilot Bearing Replacement in Clutch.
  2. Install the transmission. Refer to Transmission Replacement .

Did you find and repair the condition?

Go to Step 16

Go to Step 14

14

Disassemble and inspect the gear shift components and/or synchronizers for damage or wear. Refer to Transmission/Transaxle/Transfer Case Unit Repair Manual.

Are the gear shift and/or synchronizers worn or damaged?

Go to Step 15

Go to Step 1

15
  1. Replace worn and/or damaged components as necessary.
  2. Inspect for other gear train damaged components.

Did you find and repair the condition?

Go to Step 16

Go to Step 1

16

Operate the system and verify the repair.

Did you correct the condition?

System OK

Go to Step 1