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