Quote:
Originally Posted by deaconblues
The tranny oil and filter were replaced without incident -pan was free of ominous debris and the transmission works smoothly. Question- I understand there is a set of needle bearings that are vulnerable to failure in the 722.6, later replaced by a more robust bushing. Mine, being a '97, is likely the earlier version. Anything I can do to prolong the life of these bearings? What impact on transmission life does starting in 2nd gear (setting "W") versus 1st gear ("S") have?
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The early 722.6 had brass bushing between input and output shafts. Later (about 2000?) MB replaced it with needle bearing and seal. The problem with original design was that as bushing was getting worn the clearance would increase and as a result lubrication pressure was lost. It would cause oil starvation in the rear gearset and bearings. I have a very limited experience rebuilding 722.6 in my car (99ML430). The clearance in the bushing was about .040
I don't think you could prevent that, and don't think ATF change would help much. I've done two changes in 150000 and still had failure. Just enjoy your car and fix it when required.
See pictures here:
http://www.peachparts.com/shopforum/showthread.php?t=198186
Mike