Service Information: Replace radial sealing ring on the drive pinion gear

We have recently discovered that there has been an increase in damage cases for the ring gear and pinion on the rear axles with model designation 746.21. Tests have shown that, in most cases, improper removal and installation of the rear axle's drive flange has been the cause of these damage cases. The work procedure for this axle is described in the repair instruction

"AR35.30-T-4670BA Remove/install radial sealing ring on drive pinion".

The work procedure for replacing the radial sealing ring on the drive pinion of the rear axle with model designation 746.217 heavily deviates from the previous work procedure due to design reasons.

For this reason, we urgently advise you to strictly follow the repair instructions in AR35.30-T-4670BA when removing the drive flange from the rear axle.

 It is very important to measure the friction value before removing the drive flange. This measurement is the basis for setting the pretension of the tapered roller bearing in the axle housing after reassembling.

If this pretension value is not reached or is considerably exceeded, sever damage can occur to the bearings and gears causing the necessity of completely replacing the rear axle's ring and pinion gears.