Drive axle “howls”, unwanted sounds in the differential

Main reasons:

1) Low oil level

  • Gland seal of the pinion gear is damaged.
  • Gland seal of the half axles are damaged.
  • Breather is contaminated or damaged.
  • Loose fitting clog of the filler opening or drain hole.
  • Differential cover leaks.
  • Damage of the sealing gaskets.

2) Contaminated transmission oil

  • Oil contains big amount of moisture and (or) contaminations.

3) Transfer gear box or differential are broken.

  • Big clearance in bearings of the pinion gear.
  • Improper adjustment or wear of gears.
  • Stiff rotation of spider pinion on the axle.
  • Scratches on the operating surface of the spider pin.
  • Sticking of gears or half axles in the differential compensating case.
  • Improper clearance between gear teeth of the differential.

4) Wear of the half axle bearings.

5) Wear of the spline joint with side gears.

6) Half axles are misshaped or have inappropriate jumping.

7) Loosening of crankcase hold-down bolts of axle gearbox, unfastening of pinion nut, ring gear or swash.

Изображение проблематики


1) Car operation with a low transmission oil level leads to overheating and further wear of bearings and toothed gears of the transfer gear box and differential. By wear of the drive axle unwanted raised noise (roar) appears in different operational modes. It is recommended first to denote and to eliminate the reason of leakage for restoration of such wear. In case if the reason of the leakage is in low elasticity and uncritical wear of pinion gear glands or half axle glands, it is recommended to add into transmission oil the agent for elimination of oil leakages from units JET 100 SEALER – synthetic formula – the product for elimination of transmission oil leakage, which will help to restore glands elasticity and eliminate the leakage. If the reason of leakage is in damage of breather, gapping of plugs, damage of sealing gaskets or gapping of the differential cover, such reasons can be removed with the help of replacement or repair. After the elimination of the reason of leakage and adding oil up to the normal level, it is recommended to introduce into the transmission oil one of the types of XADO Revitalizant® products for manual gear boxes to restore the worn bearings ant toothed gears.

Note: By considerable wear close to extreme or in case of insufficient effect after the application of XADO Revitalizant® for manual gear box and 1,800–3,100 miles of run it is recommended to additionally introduce XADO Repairing grease into the warmed up transmission oil in amount not exceeding 2% of the volume of the oil bath.

2) Quick wear of bearings and toothed gears also happens after short run of the car by penetration of large amount of contaminations and moisture into the transmission oil. In this case it is recommended to change the transmission oil with a flush of inner cavity of the axle and using new transmission oil to conduct a treatment with one of the XADO Revitalizant® products for manual gear boxes.

3) In case of malfunction of transfer gear box it should be replaced: the replacement of 100% worn parts and accurate regulation of clearances. After the adjustment of the repaired gear system and short run-in period (60−190 miles) and by no assembling defects of for provision of perfect adjustment of the installed parts and protection from future wear, it is recommended to threat the axle with one of the XADO Revitalizant® products for manual gear boxes.

XADO Revitalizant® products for manual gear boxes, which are suitable for all the above situations:

4) In case of critical wear of half axle bearings, they should be replaced.

5) By 100% wear of the spline joint with side gears, they should be replaced.

6) Loosening of crankcase hold-down bolts of axle gearbox, unfastening of pinion nut, unfastening or swash of the ring gear should be removed by applying proper tightening force.


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