The numbers below refer to the step numbers on the diagnostic table.
This step inspects for vibration causing a noise. If the vehicle is equipped with an aftermarket box, or is carrying a certain load, the driveline axle may not be correct, and could cause a vibration. The vibration maybe resonating into the transmission, causing a noise.
This step inspects for the correct transmission fluid level. If the transmission fluid level is excessively low, damage may have occurred to the transmission components.
This step inspects for the correct type of transmission fluid. The transmission uses a special fluid. If the incorrect fluid was used, there may have been an overheating problem. Overheating may cause damage to the transmission components.
This step inspects for noise coming into the driver compartment. Improper sealing of the shift tower may be allowing normal transmission noise to be heard by the driver.
This step tests to determine if clutch components are making the noise. Depress the clutch pedal slowly and listen for the change in noise. If the noise changes while pressing the pedal, it may be a faulty clutch component. If the noise does not change until the clutch is completely disengaged, the transmission component is faulty.
Step | Action | Yes | No | ||||||||||||
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DEFINITION: The transmission is making a noise. The different noises may be a whine or a growl from faulty bearings or gears. The noise may also be caused from a faulty component causing a vibration noise or rattle. | |||||||||||||||
1 | Did you review the Symptoms - Manual Transmission, and perform the necessary inspections? | Go to Step 2 | |||||||||||||
Is the noise present at a certain road speed, or with a certain load? | Go to Step 3 | Go to Step 4 | |||||||||||||
3 | Inspect for the correct driveline angle. Refer to Driveline Working Angles Measurement in Vibration Diagnosis and Correction. Did you find and repair the condition? | Go to Step 23 | Go to Step 4 | ||||||||||||
4 | Is the noise present in all gears? | Go to Step 6 | Go to Step 5 | ||||||||||||
5 | Is the noise present in just one gear? | Go to Step 22 | Go to Step 6 | ||||||||||||
Inspect the transmission fluid level. Is the fluid level correct? | Go to Step 8 | Go to Step 7 | |||||||||||||
7 | Add transmission fluid. Refer to Transmission Fluid Replacement . Did you find and repair the condition? | Go to Step 23 | Go to Step 8 | ||||||||||||
Inspect the transmission for the correct fluid type. Refer to Transmission Fluid Replacement . Is the transmission fluid the correct type? | Go to Step 10 | Go to Step 9 | |||||||||||||
9 | Drain and fill the transmission with the correct type of transmission fluid. Refer to Transmission Fluid Replacement . Did you find and repair the condition? | Go to Step 23 | Go to Step 10 | ||||||||||||
Inspect the shift tower boot. Is the closeout boot loose or damaged? | Go to Step 11 | Go to Step 12 | |||||||||||||
11 | Position and tighten the shift tower boot to specifications. Refer to Control Lever and/or Boot Replacement . Did you find and repair the condition? | Go to Step 23 | Go to Step 12 | ||||||||||||
12 | Is the vehicle equipped with a power take off (PTO)? | Go to Step 13 | Go to Step 16 | ||||||||||||
13 | Remove the PTO, in order to confirm that the PTO is not the cause of the noise. Is the noise still present? | Go to Step 16 | Go to Step 14 | ||||||||||||
14 | Inspect the countershaft gear for damage from the PTO. Is the countershaft gear damaged? | Go to Step 22 | Go to Step 15 | ||||||||||||
15 | Reinstall the PTO. Ensure it is properly shimmed. Refer to the PTO manufactures installation procedure. Is the noise still present? | Go to Step 16 | Go to Step 23 | ||||||||||||
16 | Is the vehicle equipped with a transfer case? | Go to Step 17 | Go to Step 18 | ||||||||||||
17 | Engage the transfer case in the different modes. Is the noise still present or the same? | Go to Step 18 | Go to Symptoms - Transfer Case in Transfer Case NVG 149-NP3 (One Speed Automatic) or Symptoms - Transfer Case in Transfer Case NVG 236/246-NP8 (Two Speed Automatic) or Symptoms - Transfer Case in Transfer Case NVG 261-NP2 (Two Speed Manual) or Symptoms - Transfer Case in Transfer Case NVG 263-NP1 (Selectable) | ||||||||||||
18 |
Are there any loose transmission mounting bolts? | Go to Step 19 | Go to Step 20 | ||||||||||||
19 | Replace and tighten the transmission mounting bolts. Refer to Transmission Mount Replacement . Is the noise still present? | Go to Step 20 | Go to Step 23 | ||||||||||||
With the engine operating, depress the clutch pedal. Is the noise still present? | Go to Step 21 | Go to Step 22 | |||||||||||||
21 |
Did you find and repair the condition? | Go to Step 23 | Go to Step 22 | ||||||||||||
22 |
Did you find and repair the condition? | Go to Step 23 | -- | ||||||||||||
23 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 1 |