Initial Inspection and Diagnostic Overview

Inspection and Verification

CAUTION: If transmission noise is reported, first check the fluid level. The vehicle should not be driven if the fluid level is low.

NOTE: If any evaluation or inspection reveals an obvious concern, repair the vehicle.

NOTE: Before attempting to rectify any concerns, road test the vehicle to ascertain in which system the concern falls.

The technician should have a thorough knowledge of transmission/clutch operation and accepted general transmission/clutch guidelines to detect any problems.

A gear driven unit will produce a certain amount of noise. Some noise is acceptable and audible at certain speeds or under various driving conditions.

Certain conditions, such as, road and weather, will amplify normal vehicle noise.

This overview is a guide to diagnose a transmission/clutch concern:
^ Verify and document the customer concern.
- During the customer interview, if a leak was noticed or if a leak is the concern, check the transmission fluid. The vehicle should not be driven if the fluid level is low.
^ Check fluid level and condition.
^ Evaluation of the clutch hydraulic system.
^ Evaluation of the clutch.
^ Inspect gearshift mechanism.
^ Road test.
^ Find the cause of the problem and correct it.

Verify Customer Concern
1. Verify and document the customer concern.
1. When was it first noticed?
2. Did it appear suddenly or gradually?
3. Did anything unusual occur that would coincide with it or precede it?
4. Identify when the condition occurs:
^ Hot or cold vehicle operating conditions.
^ Type of terrain.
^ City/highway driving.
^ Driving at a particular speed.
- coasting.
- hard acceleration.
^ Shifting.
- upshifts.
- downshifts.
- in a particular gear.
- in all gears.
^ Hot or cold ambient temperatures.
5. Has the transmission/clutch been repaired before or components installed?
^ Check the vehicle service record. Note any repairs.
6. Check TSBs.

Check Fluid Level and Condition

CAUTION: The vehicle should not be driven if the fluid level is low.

CAUTION: Excessive temperatures may break down the transmission lubricant. If there is reason to believe that the transmission has been subjected to temperatures exceeding 275°F, change the lubricant immediately.

An incorrect level may affect the transmission operation and can result in transmission damage. To correctly check and add fluid to the transmission, refer to Specifications.

A low fluid level can result in poor transmission shifting, engagement or damage. It can also indicate a leak in one of the transmission seals or gaskets.
1. Check the fluid condition.
^ Observe the color and the odor of the fluid. Allow the fluid to drip onto a white cloth and examine the stain. Check the fluid for contamination or metal particles.
^ Fluid should appear reddish in color.

Evaluation of Clutch Hydraulic System
1. Verify that the clutch hydraulic fluid reservoir is filled to the correct level.
^ If the fluid level is correct, proceed to clutch check.
^ If the fluid level is low, add fluid as necessary. Check the clutch hydraulic system for leaks and repair as necessary.

Evaluation Of The Clutch
1. Depress and release the clutch pedal slowly to check if the pedal is binding. Make sure the clutch pedal can be fully depressed and is not restricted by the floor mat.
2. Measure the clutch reserve. GO to Pinpoint Test A. Test A: Clutch Slippage
3. With the engine idling, the parking brake on and the clutch pedal up, gently move the gearshift lever forward into and out of REVERSE gear, until gear clash can be heard. Depress the clutch pedal slowly.
^ If the gears cease to clash (full disengage at 1 to 1.5 inch from the floor), then hold the pedal at the point of disengagement and increase engine to 4,000 rpm. The clutch should remain disengaged, clutch OK.
^ Any concerns indicate a worn or damaged clutch. Repair as necessary.
4. With the engine idling, move the gearshift lever into 4th gear. Increase the rpm to 2,000 and slowly release the clutch pedal.
^ If the engine stalls, clutch is OK.
^ If the engine does not stall, clutch slipping. Repair as necessary.
5. Compare the clutch evaluation results with the table. The list of conditions are typical faults into which clutch concerns will fall.

Symptom Chart

Symptom Chart (Part 1):

Symptom Chart (Part 2):

Inspect The Gearshift Mechanism
1. Inspect the gearshift mechanism for:
^ signs of damage.
^ missing or loose fasteners.
^ binding.
2. Repair any concerns as necessary.

Road Test the Vehicle
1. During the road test, use these driving methods to diagnose the problem.
^ Start the engine.
^ Evaluate the noise in NEUTRAL while the vehicle is parked.
- Check whether the noise is present with the clutch fully disengaged (pedal fully depressed). Check to determine if the pedal pulsates abnormally (for clutch diaphragm finger run out).
- Check whether the noise is present with the gearshift in the NEUTRAL position and the clutch fully engaged (foot off pedal). With the parking brake engaged, move the gearshift towards the 1st gear position. Apply very slight pressure and note if the gear noise level is reduced. (for gear rollover noise).
- With the clutch fully engaged (foot off pedal) check whether the noise is present as the engine speed is raised. If the noise reduces, note the engine speed at which this occurs.
* For single mass flywheel: function.
^ Listen for any change in noise while depressing and releasing the clutch pedal.
^ Listen for any change in noise while changing the engine rpm.
^ Drive the vehicle and shift through all of the gear ranges, including reverse. Listen for any change in noise in a particular gear.
^ Drive the vehicle in the gear in which the noise is most noticeable. Depress the clutch pedal and leave the gear engaged. Listen for any change in noise.
^ Drive the vehicle in the gear in which is most noticeable. Depress the clutch pedal and shift the transmission into NEUTRAL. Release the clutch pedal and allow the vehicle to coast.
2. Compare the road test results with the symptom chart. It is a list of conditions that are typical faults into which the transmission will fall: GO to Symptom Chart. Symptom Related Diagnostic Procedures