Cause | Correction |
|---|---|
Inspect for the proper gear oil levels prior to performing system diagnosis. Refer to Axle Lubricant Change . | |
Incorrect type fluid Installation of the incorrect type gear oil may create a "moan" type noise within 7 770-25 900 km (3-10,000 miles). Fluid that is "black" in color is to be considered normal and is darkened by the carbon material in the clutch plates. | Replace the rear differential assembly as required. Fluid replacement will not correct a "moan" condition caused by the use of incorrect oil. Refer to Differential Replacement . |
Water or contamination within the transmission oil Water or contamination within the transmission fluid, causing excessive torque converter clutch slip rate, may create a "grind, growl, or moan" in the rear differential or torque tube under light or steady load conditions. | Replace the transmission fluid and flush the transfer case of the contaminated fluid. Refer to Internal Components Cleaning and Inspection. |
Loose propeller shaft mounting bolts | Tighten the bolts as required. Refer to Propeller Shaft Replacement. |
Worn propeller shaft constant velocity joints | Replace propeller shaft assembly. Refer to Propeller Shaft Replacement. |
Worn axle shaft constant velocity joints | Replace the constant velocity joints as required. |
Worn, loose, or missing differential mounts | Repair or replace the differential mounts as required. |
Loose torque tube bracket or a worn bracket bushing | Tighten the bracket bolts or replace the bracket as required. |
Worn bearing in the torque tube assembly | Replace the torque tube assembly |
Torque tube dampner loose or missing A "moan" or "exhaust leak" type noise at higher engine speeds, approximately 2,000-2,500 RPM, may indicate a loose or missing dampner. | Tighten the dampner retaining bolt or replace the torque tube assembly as required. |
Bearing noise within the differential assembly A "grinding" or "roar" type noise will increase or decrease relative to the vehicle speed. |
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Gear set "whine" noise within the differential assembly A "whine" type noise will increase or decrease relative to the vehicle speed approximately 80-97 km/h (50-60 mph). |
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