Mercedes-Benz W140 rear axle whine and oil leak
W140 rear end whines under load, what is the cause?
The whine is usually caused by the rear axle bearings. Bearing play affects the backlash between the gears, and later the bearing starts to growl. If the rear axle has had too little oil, the tooth surfaces may be damaged and make the same noise.
What torque is the driveshaft flange center nut tightened to?
Models 140.03, 140.04 and 140.1 require 180 Nm. Models 140.05 and 140.07 require 125 Nm. The nut is in the middle of the driveshaft joint.
W140 rear axle leaks oil from the driveshaft side, can the seal be replaced without removing the axle?
Yes. The oils are drained, the driveshaft is swung aside and the flange nut is opened with a long 30 mm socket. The nut is marked and the handbrake is kept on. The new seal is driven into place, the driveshaft is assembled in the same position and about 1.4 litres of oil is filled in.
Oil comes out of the breather on top of the rear differential, what causes it?
The breather can become blocked with rust, which pushes the oil out. The valve comes off with a roughly 15 mm wrench, and it can be cleaned.