Transmission Seal Leakage

[placervillebob]

2004 S80 2.9L non-turbo Auto FWD 88,000 mi. Non-Viscous clutch
After replacing my Right (Passenger) side Drive Shaft, I am now having a little leakage at the Transmission Seal (where the shaft plugs into the tranny). Everything went fine during the remove & replace, however when the old shaft was slid out of the transmission, about a pint or so of transmission fluid drained out – IS THIS NORMAL? The seal was evidently keeping this fluid contained. When I completed installing the new shaft, I replaced the pint of fluid and took it out for a test drive. Everything looked and felt good – no leaks at that point. After checking the transmission fluid level – I found it was a little high – wish I hadn’t put in that pint. After a week or two of driving I have developed a leak coming from the seal/shaft area. I have a few questions:
- Should I replace the seal & how difficult a job is it? Is it a pry it out and tap the new one in type of job?
- Should I remove the shaft and let the trapped fluid drain and re-install the shaft – but this time don’t replace lost fluid?
- Is there supposed to be tranny fluid in this area or is that a result of over-filling?
- What sort of function does this seal provide? Is it to keep dust/dirt out (like a wheel bearing seal) or is it to keep tranny fluid in – in other words is this an active reservoir of the transmission fluid?
Any comments would be appreciated.

Thanks
placervillebob

[fn42]

I havent had a chance to touch my s80 trans yet but transverse/FWD transmissions DO leak when an axle is removed. The few times I have pulled axles I have stuffed rags in the axle hole just to prevent the fluid from leaking on the ground. It is also common practice to replace the axle seal while you have the axle out, they're not hard to replace but it does require removing the axle.

It's a pry out and tap in job, just like any other circular seal - it's job is to seal between the axle and the transmission so fluid does not leak out

[placervillebob]

Thanks for the reply.
I was able to get under the car last night for a closer look and tried to measure to see what size of seal I needed. Apparently there are two sizes - 42mm and 47mm outside dia. I set my calipers to 42mm and that size is smaller than the drive shaft that goes into the seal so when setting it to 47mm it looked like it was measuring the outside of the rubber only. Question is when replacing this seal is it only the rubber seal that gets replaced or is it contained in a housing that gets installed into the transmission. Kind of difficult to describe but I hate to pry something out of the tranny that isn't supposed to be removed.
Visually the old seal looks good - no cracks or voids against the machined surface of the shaft.
Thanks for any comments.
placervillebob