GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

Hard shifting can be diagnosed easily. You should perform a static shift test and a dynamic shift test. Many other simple factors could occur, such as insufficient fluid, excessive fluid or even the wrong transmission fluid. A misaligned transmission can also cause hard shifting, as well as a worn or defective clutch, or binding of the shift control. Many internal components can also play a factor in hard shifting, such as a front bearing retainer loose or cracked, synchronizer worn, damaged or improperly assembled. Failure to fully depress the clutch pedal when shifting will cause hard shifting.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step test for air in the hydraulic lines, also causing the transmission to shift hard.

  2. This step inspects for a faulty shift control.

  3. This step inspects for faulty or worn clutch pressure plate or clutch driven plate.

Step

Action

Yes

No

DEFINITION: The transmission does not shift smoothly or without difficulty into another gear.

1

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

Go to Step 2

Go to Symptoms - Manual Transmission

2

Verify that the reverse lockout solenoid circuit is functioning properly.

Is the reverse lockout solenoid circuit functioning properly?

Go to Step 3

Go to Step 4

3

Review the reverse lockout solenoid circuit, repair or replace components as necessary.

Did you find and repair the condition?

System OK

Go to Step 4

4

Replace the reverse lockout solenoid. Refer to Reverse Lockout Solenoid Replacement .

Did you find and repair the condition?

System OK

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 air from the clutch hydraulic system. Refer to Hydraulic Clutch Bleeding in Clutch.

Did you find and repair the condition?

System OK

Go to Step 7

7

Inspect the transmission shift control for binding.

Is the transmission shift control binding?

Go to Step 8

Go to Step 9

8

Replace the transmission shift control. Refer to Shift Control Assembly Replacement .

Did you find and repair the condition?

System OK

Go to Step 9

9

Inspect the transmission for the correct type transmission fluid.

Is the correct type fluid being used?

Go to Step 11

Go to Step 10

10

Drain and refill the transmission with the correct type fluid. Refer to Transmission Fluid Replacement .

Did you find and repair the condition?

System OK

Go to Step 11

11

Inspect the clutch pressure plate and/or clutch driven plate.

Is the clutch pressure plate and/or clutch driven plate worn or faulty?

Go to Step 12

Go to Step 13

12

Replace the clutch pressure plate and/or clutch driven plate. Refer to Clutch Assembly Replacement in Clutch.

Did you find and repair the condition?

System OK

Go to Step 13

13

  1. Remove the transmission. Refer to Transmission Replacement .
  2. Inspect the transmission for an internal bind possibly caused by one of the following:
  3. • Shift forks
    • Selector plates
    • Synchronizers

Is there an internal bind?

Go to Step 14

--

14

  1. Replace worn or damaged components as necessary. Refer to Transmission Disassemble in the Transmission Unit Repair Manual.
  2. Install the transmission. Refer to Transmission Replacement .

Did you find and repair the condition?

Go to Step 15

Go to Diagnostic Aids

15

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 1