Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra and 2004 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

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

2: This step tests for the proper releasing of the clutch. If the clutch reserve is not proper, the mainshaft gears may still be turning, causing gear clash.
5: This step inspects for the proper transmission fluid. A special fluid is required for the correct lubrication of the synchronizers.
7: A static shift test is performed by shifting into all of the gear positions with the engine not operating. While performing the test, you should note how the shift lever movement is felt. Also, while shifting from one gear to another, feel for binding in the shift rails. You should be able to feel the detent plungers operating when coming out of a gear and going into a gear. Excessive play in the gear shift lever may prevent the shift forks from fully engaging the synchronizer.
9: A dynamic shift test is performed by shifting into all of the gear positions with the engine operating. Test for the correct mesh of the synchronizers, and for the clutch releasing correctly. Move the shift lever and feel for the synchronizer sleeve to just release from the gear, then let up on the clutch pedal. Depress the clutch pedal and move the shift lever to engage that gear again. If it shifts back into the gear without clashing, the clutch is releasing correctly and the synchronizer is working. If clashing occurs, test on another gear. If all gears clash, the clutch is not releasing correctly.

Transmission Gear Clash When Shifting Gears

Step	Action	Yes	No
DEFINITION: Noise from the transmission when shifting gears. A grinding or grating sound when the synchronizer sleeve is engaging with the selector teeth on the speed gear. A suspected internal transmission condition if the noise only occurs in one gear.
1	Did you review the Symptoms - Manual Transmission and perform the necessary inspections?	Go to Step 2	Go to Symptoms - Manual Transmission
2	With the engine operating, does the transmission shift from neutral to any gear, without the vehicle lurching or gear clashing?	Go to Step 5	Go to Step 3
3	Inspect for proper clutch operation. Refer to Clutch System Description and Operation in Clutch. Does the clutch operate properly?	Go to Step 5	Go to Step 4
4	Repair the clutch system. Refer to Symptoms - Clutch in Clutch. Did you find and repair the condition?	Go to Step 11	Go to Step 5
5	Inspect for the correct transmission fluid level and the proper fluid. Refer to Transmission Fluid Replacement . Is the transmission fluid level correct and at the proper level?	Go to Step 7	Go to Step 6
6	Fill the transmission fluid to the correct level or change the transmission fluid if it is not the correct type. Does the transmission still have gear clash?	Go to Step 7	Go to Step 11
7	Perform a static shift test on the transmission. Test for the following: Blockage, preventing full shift lever movement Excessive movement in the shift lever Binding in the shift lever Detent plungers or shift rails binding Did the transmission shift smoothly into the gear that is clashing?	Go to Step 9	Go to Step 8
8	Remove the shift lever and inspect for damage or worn components. Refer to Shift Lever Assembly Replacement . Did you find and repair the condition?	Go to Step 11	Go to Step 9
9	Perform a dynamic shift test on the transmission. Test for the following: Detent plungers or shift rails binding Synchronizer sleeve binding Gear clashing in more than the suspected gear Is the transmission hard to shift into all gears?	Go to Transmission Shifts Hard	Go to Step 10
10	Disassemble the transmission. Refer to Transmission Disassemble in Manual Transmission - ZF S6-650 Unit Repair. Inspect the following transmission components for the gear that is clashing: Excessive synchronizer blocking ring to gear clearance Synchronizer sleeve to hub clearance excessive Excessive axial clearance in the speed gear Mainshaft to speed gear bearing or journal worn Shift fork worn or damaged Internal shift control worn or damaged Mainshaft bearing worn or damaged Input gear bearing or pilot bearing worn Did you find and repair the condition?	Go to Step 11	Go to Diagnostic Aids
11	Operate the system and verify the repair. Did you correct the condition?	System OK	Go to Step 1