I'm glad that someone on the H.A.M.B. was able to answer your question, Pete.

I JUST read your posting, but was scratching my head on the answer for the question.  -It's been awhile!  

Whether it was a T-86 w/ the R-10 od or a T-85 with the R-11 overdrive, the answer should be the same because of their similarity in construction.

Your '56 Merc should have a T-85 with the 9 bolt curved bottom side cover.  -10 spline clutch disc input shaft, 16 spline ~1 1/4  inch O.D. output shaft.
Click the link below to see a picture of a '56 vintage T-85 w/ ovrdrive  [NOTE: you'll need to scroll down on the page that opens]
http://www.ebay.com/itm/T85C-1A-transmission-with-overdrive-/221914115163?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2047675.l2557&nma=true&si=hATz5cnvxT5qynNHYr6baFpjxhs%253D&orig_cvip=true&rt=nc 

Let us know how replacing that 'O' ring goes...

Regards,


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

I got an answer over on the HAMB. So to those who are curious the seal can be replaced with the tranny in the car.
Pete

The T86 in my 56 Merc is leaking from the overdrive lockout lever at the transmission. I know that there is a seal in there that installs from the outside of the case. I am also aware that there is a taper pin that if driven up from the bottom will allow the lever and shaft to be at least partially extracted from the trans case.
The shop manual states all of that in the disassembly instructions. What is not stated is if the lever can be fully extracted to allow replacement of the seal and if removal of the shaft will cause anything to pop out of place .
So the question here is directed to anyone that may have knowledge of these transmissions to tell me if it is possible to change that seal with the trans in the car ? I have plenty of room around the unit just unsure how to proceed. Any help appreciated.

Pete