The seal on the rear shaft on my transmission is leaking, can anbyone give me an estimate on time to replace, is this a big job??

If you are talking about an automatic and it is high mileage chances are the rear bushing is worn and that allowed the seal to wear. Grab the rear flange on the output shaft and see how much lateral play there is. If it is more than about a 1/16" you probably won't gain much time in steming the flow by just replacing the seal.

Replacing the bushing involves removing the rear flange and then the rear housing on the transmission before you can get at the bushing. IPD does offer the rental of a tool that allows the removal of the bushing without removing the rear housing but I have no experience with that particular device. Once I have the rear housing off of the car I take it to a shop and have them swap out the bushing. If you decide to tackle it yourself you may want to post again for tips and advice. As far as skill level goes I would say it is more difficult than a timing belt/seals job but not as involved as a rear main seal replacement : -)

Randy

Manual or automatic transmission?

Sorry, Automatic, 157K miles on it

If it is your transmission tailshaft leaking (and it probably is), you need to replace the bushing and seal. The bushing wears, and just replacing the seal won't fix it for long. IPD sells the bushing and seal for about $28. Don Foster had a nice post on this, with pictures, some time ago. I think he cut the old bushing out with a hacksaw blade, rather than renting IPD's tool. You might try a search in the archives. Check with an auto tranny shop. I wouldn't expect more than an hour of labor for this job.

Joe, my rear main was leaking. I changed the flame trap and also found that the passage into the top of the intake was clogged solid. Cleared it out, replaced flame trap, no more leaky rear seal. 86 245 w/ 358K original driveline.

John, I think Joe means the rear transmission seal, the one that is on the tailshaft of the tranny as it exits the housing. I believe you, on the other hand, are referring to the rear engine oil seal.