GM Service Manual Online
For 1990-2009 cars only

Complaint/Condition

Possible Cause

correction

Knock at Low Speeds

    â€¢ Worn drive axle joint
    â€¢ Worn side gear or pinion gear bores
    â€¢ Inspect drive axle joint and replace if necessary.
    â€¢ Inspect differential case and replace if necessary.

Noisy Around Turns

Worn differential gears

Inspect differential gears and replace if necessary.

Clunk or Acceleration or Deceleration

    â€¢ Loose engine mounts
    â€¢ Worn inboard drive axle joint
    â€¢ Worn differential pinion shaft
    â€¢ Worn side gear hub counterbore
    â€¢ Inspect engine mounts and tighten if necessary.
    â€¢ Inspect inboard drive axle joint and replace if necessary.
    â€¢ Inspect differential pinion shaft and replace if necessary.
    â€¢ Inspect side gear hub counterbore and replace if necessary.

Click Noise On Turns

Worn outboard drive axle C/V joint

Inspect C/V joint and replace if necessary.

Noisy in Neutral With Engine Running

    â€¢ Worn input gear bearing
    â€¢ Worn speed gear bearing
    â€¢ Worn bearing races
    â€¢ lnspect bearing and replace if necessary.
    â€¢ lnspect bearing and replace if necessary.
    â€¢ lnspect bearing race and replace if necessary.

Noisy in First Gear Only

    â€¢ Worn, chipped, or scored 1st speed constant-mesh gears
    â€¢ Worn, shipped, or scored 1st/2nd synchronizer
    â€¢ lnspect gears and replace if necessary.
    â€¢ lnspect synchronizer and replace if necessary.

Noisy in Second Gear Only

    â€¢ Worn, chipped, or scored 2nd speed constant-mesh gears
    â€¢ Worn, chipped, or scored 1st/2nd synchronizer
    â€¢ lnspect gears and replace if necessary.
    â€¢ lnspect synchronizer and replace if necessary.

Noisy in Third Gear Only

    â€¢ Worn, chipped, or scored 3rd speed constant-mesh gears
    â€¢ Worn, chipped, or scored 3rd/4th synchronizer
    â€¢ lnspect gears and replace if necessary.
    â€¢ lnspect synchronizer and replace if necessary.

Noisy in Fourth Gear Only

    â€¢ Worn, chipped, or scored 4th speed constant-mesh gears
    â€¢ Worn, chipped, or scored 3rd/4th synchronizer
    â€¢ Worn, chipped, or scored output gear
    â€¢ Worn, chipped, or scored output gear
    â€¢ lnspect gears and replace if necessary.
    â€¢ lnspect synchronizer and replace if necessary.
    â€¢ lnspect gear and replace if necessary.
    â€¢ lnspect gear and replace if necessary.

Noisy in Fifth Gear Only

    â€¢ Worn, chipped, or scored 5th speed constant-mesh gears
    â€¢ Worn, chipped, or scored 5th synchronizer
    â€¢ Worn, chipped, or scored output gear
    â€¢ lnspect gears and replace if necessary.
    â€¢ lnspect synchronizer and replace if necessary.
    â€¢ lnspect gear and replace if necessary.

Noisy in Reverse Only

    â€¢ Worn, chipped, or scored reverse speed constant-mesh gears
    â€¢ Worn or damaged output gear
    â€¢ lnspect gear and replace if necessary.
    â€¢ lnspect gear and replace if necessary.

Noisy in All Gears

    â€¢ Fluid level low
    â€¢ Worn or damaged wheel bearings
    â€¢ Worn, chipped, or scored input/output shaft gear
    â€¢ Worn output gear bearing
    â€¢ Loose shift rail guide bolt
    â€¢ Worn, chipped, or scored 1st, 2nd, 3rd, 4rd, 5th, or Reverse gears.
    â€¢ Add fluid to proper level.
    â€¢ Inspect wheel bearing and replace if necessary.
    â€¢ Inspect gear and replace if necessary.
    â€¢ Inspect output gear bearing and replace if necessary.
    â€¢ Tighten shift rail guide bolt.
    â€¢ Inspect components and replace as necessary.

Slips Out of Gear

    â€¢ Loose transaxle mounts
    â€¢ Bent or worn cables
    â€¢ Broken or loose input gear bearing retainer
    â€¢ Worn or bent shift fork
    â€¢ Dirty clutch housing and engine
    â€¢ Stiff shift lever seal
    â€¢ Manual transaxle internal shift mechanism malfunction
    â€¢ Tighten or replace mounts.
    â€¢ Inspect cables and replace if necessary.
    â€¢ Inspect shift fork and replace if necessary.
    â€¢ Inspect shift fork and replace if necessary.
    â€¢ Clean clutch housing and engine.
    â€¢ Inspect seal and replace if necessary.
    â€¢ Disassemble transaxle, repair as necessary.

Slips Out of Gear While Accelerating

    â€¢ Missing or misadjusted first gear thrust bearing or washer
    â€¢ Worn or damaged fist gear spline lock on 1st/2nd synchronizer
    â€¢ Worn of damaged second gear spline lock on 1st/2nd synchronizer
    â€¢ Worn or damaged third gear spline lock on 3rd/4th synchronizer
    â€¢ Worn or damaged fourth gear spline lock on 3rd/4th synchronizer
    â€¢ Worn or damaged 5th gear spline lock on the 5th/Reverse synchronizer
    â€¢ Worn or damaged Reverse gear spline lock on the 5th/Reverse synchronizer
    â€¢ Worn or damaged 1st, 2nd, 3rd, 4th, 5th or reverse gear spline lock
    â€¢ Manual transaxle internal shift mechanism malfunction
    â€¢ Inspect bearing and washer and replace if necessary.
    â€¢ Inspect spline lock and replace if necessary.
    â€¢ Inspect spline lock and replace if necessary.
    â€¢ Inspect spline lock and replace if necessary.
    â€¢ Inspect spline lock and replace if necessary.
    â€¢ Inspect spline lock and replace if necessary.
    â€¢ Inspect spline lock and replace if necessary.
    â€¢ Inspect spline lock and replace if necessary.
    â€¢ Disassemble transaxle, repair as necessary.

Slips Out of Gear While Coasting

    â€¢ Damaged, worn, or missing shift rails
    â€¢ Manual transaxle internal shift mechanism malfunction
    â€¢ Inspect shift rails and replace if necessary.
    â€¢ Disassemble transaxle, repair as necessary.

Fluid Leakage

    â€¢ Fluid level high
    â€¢ Damaged axle shaft seals
    â€¢ Vent cap plugged
    â€¢ Poor sealing on shift cover
    â€¢ Poor sealing between case and clutch housing
    â€¢ Poor sealing on rear cover
    â€¢ Poor sealing or loose back-up lamp switch
    â€¢ Poor sealing or loose vehicle speed sensor
    â€¢ Drain excess fluid.
    â€¢ Inspect axle shaft seals and replace if necessary.
    â€¢ Clear or replace vent cap.
    â€¢ Replace sealer on shift cover.
    â€¢ Replace sealer between case and clutch housing and tighten.
    â€¢ Replace sealant on rear cover and tighten.
    â€¢ Tighten switch or replace sealant as needed.
    â€¢ Tighten sensor or replace sealant as needed.