Mr 64,

You are welcome,

To fix the reverse problem only, the problem is at the front of the transmission-right next to the main oil pump. You just have to remove the oil pump, compress the springs on the B3 with a homemade PVC plumbing coupling and remove the round snap ring; Separate the B3 from the oil pump, and it is the inner lip-seal on the B3.

The first picture-B3 piston with inner o-ring
Second picture-B3 scored on the inside from hitting the K2 clutch pack which is the click-click roller coaster sound while in reverse.
Third Picture-inside 5dollar lip seal

no reverse / jerks in reverse when cold - Benzworld.org - Mercedes-Benz Discussion Forum

To get to the lip seal:

Step 7 the lip seal
Step 9 the oil pump-lift the inner round gear and wedge for scoring-they should look smooth at the base.If it is scored, you will have to replace the whole pump, or the parts.

If you elect to fix reverse only, just replace all the parts in the last picture, and try not remove K2(the first picture on post19 from the previous link) clutch pack, because it is a pain to line-up the individual clutches.

Do not forget to change the front torque converter seal...

722.5 transmission oil pump rebuid DIY - Benzworld.org - Mercedes-Benz Discussion Forum

Best of luck,

Martin