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Home >> Buick >> 2015 >> Regal GS, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 6 (Manual Transaxle - F40) >> Diagnostic Information and Procedures >> Symptoms - Manual Transmission

Symptoms - Manual Transmission

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Complaint/Condition Possible Cause correction
Knock at Low Speeds
  • Worn drive axle joint
  • Worn side gear or pinion gear bores
  • Inspect drive axle joint and replace if necessary.
  • 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
  • Loose engine mounts
  • Worn inboard drive axle joint
  • Worn differential pinion shaft
  • Worn side gear hub counterbore
  • Inspect engine mounts and tighten if necessary.
  • Inspect inboard drive axle joint and replace if necessary.
  • Inspect differential pinion shaft and replace if necessary.
  • 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
  • Worn input gear bearing
  • Worn speed gear bearing
  • Worn bearing races
  • Inspect bearing and replace if necessary.
  • Inspect bearing and replace if necessary.
  • Inspect bearing race and replace if necessary.
Noisy in First Gear Only
  • Worn, chipped, or scored 1st speed constant-mesh gears
  • Worn, shipped, or scored 1st/2nd synchronizer
  • Inspect gears and replace if necessary.
  • Inspect synchronizer and replace if necessary.
Noisy in Second Gear Only
  • Worn, chipped, or scored 2nd speed constant-mesh gears
  • Worn, chipped, or scored 1st/2nd synchronizer
  • inspect gears and replace if necessary.
  • inspect synchronizer and replace if necessary.
Noisy in Third Gear Only
  • Worn, chipped, or scored 3rd speed constant-mesh gears
  • Worn, chipped, or scored 3rd/4th synchronizer
  • inspect gears and replace if necessary.
  • inspect synchronizer and replace if necessary.
Noisy in Fourth Gear Only
  • Worn, chipped, or scored 4th speed constant-mesh gears
  • Worn, chipped, or scored 3rd/4th synchronizer
  • Worn, chipped, or scored output gear
  • Worn, chipped, or scored output gear
  • inspect gears and replace if necessary.
  • inspect synchronizer and replace if necessary.
  • inspect gear and replace if necessary.
  • inspect gear and replace if necessary.
Noisy in Fifth Gear Only
  • Worn, chipped, or scored 5th speed constant-mesh gears
  • Worn, chipped, or scored 5th synchronizer
  • Worn, chipped, or scored output gear
  • inspect gears and replace if necessary.
  • inspect synchronizer and replace if necessary.
  • inspect gear and replace if necessary.
Noisy in Reverse Only
  • Worn, chipped, or scored reverse speed constant-mesh gears
  • Worn or damaged output gear
  • inspect gear and replace if necessary.
  • inspect gear and replace if necessary.
Noisy in All Gears
  • Fluid level low
  • Worn or damaged wheel bearings
  • Worn, chipped, or scored input/output shaft gear
  • Worn output gear bearing
  • Loose shift rail guide bolt
  • Worn, chipped, or scored 1st, 2nd, 3rd, 4rd, 5th, or Reverse gears.
  • Add fluid to proper level.
  • Inspect wheel bearing and replace if necessary.
  • Inspect gear and replace if necessary.
  • Inspect output gear bearing and replace if necessary.
  • Tighten shift rail guide bolt.
  • Inspect components and replace as necessary.
Slips Out of Gear
  • Loose transaxle mounts
  • Bent or worn cables
  • Broken or loose input gear bearing retainer
  • Worn or bent shift fork
  • Dirty clutch housing and engine
  • Stiff shift lever seal
  • Manual transaxle internal shift mechanism malfunction
  • Tighten or replace mounts.
  • Inspect cables and replace if necessary.
  • Inspect shift fork and replace if necessary.
  • Inspect shift fork and replace if necessary.
  • Clean clutch housing and engine.
  • Inspect seal and replace if necessary.
  • Disassemble transaxle, repair as necessary.
Slips Out of Gear While Accelerating
  • Missing or misadjusted first gear thrust bearing or washer
  • Worn or damaged fist gear spline lock on 1st/2nd synchronizer
  • Worn of damaged second gear spline lock on 1st/2nd synchronizer
  • Worn or damaged third gear spline lock on 3rd/4th synchronizer
  • Worn or damaged fourth gear spline lock on 3rd/4th synchronizer
  • Worn or damaged 5th gear spline lock on the 5th/Reverse synchronizer
  • Worn or damaged Reverse gear spline lock on the 5th/Reverse synchronizer
  • Worn or damaged 1st, 2nd, 3rd, 4th, 5th or reverse gear spline lock
  • Manual transaxle internal shift mechanism malfunction
  • Inspect bearing and washer and replace if necessary.
  • Inspect spline lock and replace if necessary.
  • Inspect spline lock and replace if necessary.
  • Inspect spline lock and replace if necessary.
  • Inspect spline lock and replace if necessary.
  • Inspect spline lock and replace if necessary.
  • Inspect spline lock and replace if necessary.
  • Inspect spline lock and replace if necessary.
  • Disassemble transaxle, repair as necessary.
Slips Out of Gear While Coasting
  • Damaged, worn, or missing shift rails
  • Manual transaxle internal shift mechanism malfunction
  • Inspect shift rails and replace if necessary.
  • Disassemble transaxle, repair as necessary.
Fluid Leakage
  • Fluid level high
  • Damaged axle shaft seals
  • Vent cap plugged
  • Poor sealing on shift cover
  • Poor sealing between case and clutch housing
  • Poor sealing on rear cover
  • Poor sealing or loose back-up lamp switch
  • Poor sealing or loose vehicle speed sensor
  • Drain excess fluid.
  • Inspect axle shaft seals and replace if necessary.
  • Clear or replace vent cap.
  • Replace sealer on shift cover.
  • Replace sealer between case and clutch housing and tighten.
  • Replace sealant on rear cover and tighten.
  • Tighten switch or replace sealant as needed.
  • Tighten sensor or replace sealant as needed.