Diagnostic Aids
Hard shifting can be diagnosed easily. You should perform a static shift and dynamic shift test. Many other simple factors could occur such as insufficient fluid, excessive fluid or even the wrong transmission lubricant. A misaligned transmission can also cause hard shifting as well as a worn or defective clutch, binding of the shift control. Many internal components can also play a factor in hard shifting such as the front bearing retainer loose or cracked, synchronizer worn, damaged or improperly assembled. A failure to fully depress the clutch pedal when shifting will cause hard shifting.
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
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This step checks for a faulty shift tower.
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The ZF S6-650 uses a synthetic transmission fluid. If other fluids were added or if the improper fluids were added, varnish may be on the syncro facing. The varnish would cause improper syncro operation.
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This step checks for a 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 | |||||||
2 | Inspect the clutch system for proper operation. Refer to Hydraulic Clutch Description in Clutch. Did you find or repair the condition? | Go to Step 10 | Go to Step 3 | ||||||
Inspect the transmission shift tower for binding. Did you find and repair the condition? | Go to Step 10 | Go to Step 4 | |||||||
4 | Replace the transmission shift tower. Refer to Shift Tower Replacement . Did you find and repair the condition? | Go to Step 10 | Go to Step 5 | ||||||
Inspect the transmission for the correct type transmission fluid. Refer to Lubrication Specifications . Is the proper transmission fluid being used? | Go to Step 7 | Go to Step 6 | |||||||
6 | Drain and refill the transmission with the correct type fluid. Refer to Lubrication Specifications . Did you find and repair the condition? | Go to Step 10 | Go to Step 7 | ||||||
Remove the transmission. Refer to Transmission Replacement . Inspect the clutch pressure pate and/or clutch driven plate. Is the clutch pressure plate and/or clutch driven plate worn or faulty? | Go to Step 8 | Go to Step 9 | |||||||
8 | Replace the clutch pressure plate and/or clutch driven plate. Refer to Clutch Assembly Replacement in Clutch. Did you find and repair the condition? | Go to Step 10 | Go to Step 9 | ||||||
9 | Disassemble the transmission. Refer to Transmission Disassemble . Inspect the transmission for an internal binding, possibly caused by one of the following:
Replace worn or damaged components as necessary. Did you find and repair the condition? | Go to Step 10 | Go to Diagnostic Aids | ||||||
10 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 1 | ||||||
