Hey,

You have be complete in one's answers, I repair peoples problems, so I have be complete... I do not like half-way answers, so I try not to do it either?

All of these 722.3's through 722.5 suffer from reverse and forward(B2 seal or Piston), yet the front bushing usually occurs with M120 cars, or the people that hot-dog their cars around with the 722.3. Now, some 722.3's came with roller bearings for the front bearing... The AMG 722.6, and 722.9's have had this bushing problem... One guy experienced this problem just recently I helped.. It is one of those links I posted on this thread..

Gearbox 722.368 repair manual / tips - Mercedes-Benz Forum

Now, some guys stick second generation 722.6(Touch-Shift +2000) transmission on these old cars as it withstand lots of torque. Verrryyyy Easy to rebuild-excellent for the first time DIY. It is an electronic transmission, but it last a long long time. To put it on a old car a few people make a controller...

http://www.peachparts.com/shopforum/performance-paddock/332843-stand-alone-722-6-tcu.html

I personally like the 722.6-no adjustments with modulators, no dog bones to deal with....
I can rebuild one from start to finish in a day...

More about the 722.6,

New revised 722.6 service manual - get it while can - Mercedes-Benz Forum

All the best,

Martin