I would think that the B3 piston lip seal leak would prevent pressure build up in the B3 piston when reverse gear is selected. If no pressure build up, then no clamping of the B3 friction discs. If no clamping, no reverse.

I believe the reverse failure is a sequence of events. First, the friction discs wear to quickly allowing the the B3 piston to much travel. Not only does the B3 piston impact the K1 carrier, it also allows the inside B3 piston lip seal to advance beyond the machined sliding surface. When the piston then retracts, the seal is damaged by dragging over the transition between the sliding surface and the unmachined shaft section. Leaking seal then results in no reverse.

Then again, I'm just an average DIY wrench........ I could be all wrong on this.

J. M. van Swaay

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1994 E320 Wagon, 230,000 miles
1995 E320 Sedan, 106,000 miles
1994 E500 Sedan, 79,000 miles

I bought the OE Mercedes seal kit when I rebuilt my transmission and the seals were NOT individually marked. It would have saved a lot of confusion if they had been marked.

great writeup...keep you posted on my build at mbworld :-)

I am not affiliated in any way..just wanted to show the kit...the discs aren't in the pic but are inluded

partskit

Pic of kit... they have blowouts of what parts are relevant per baggie:



I'm 1/3 of the way through the rebuild...if there is anything missing..I'll post here.

So how did you rebuild go? I think I'm about to take on the same task.

__________________
'94 E320 with 272,000 miles. '92 500SEL 133,000 miles.
Mods to the '94: TomTom GPS in place of ash tray, Auto Dimming Mirror ,Memory seat, DEI 545T Auto lamps, DEI 530T Auto Up/Down Windows, DEI Remote Start, Motorola Bluetooth® Car Kit, Built in phone charger using factory phone wiring, RainTracker Rain sensing wiper, Keyless Entry, Ambient lighting of center storage compartment. Soon: factory heated seats, REST
Mercedes-Benz is my addiction of choice.
http://www.youtube.com/vanwiek