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What to do about an oil leak


Active member
Sep 24, 2003
Santa Barbara, CA
Okay so heres the deal, I have a 1986 740gle with the 4 speed auto (ZF?). When i got the car the mechanic said it has a small leak in the rear main seal. It wasnt really a problem back then but 10,000 miles later its getting worse. So here are some options i thought of. I buy the seal and try to install it myself. This is cheapest but im not sure if you can change it with taking out the engine and transmission since its between them. The next option is take it to my mechanic and pay them a lot just to get it over with and done right. Final option is taking this as a sign that i need to swap a m46 in there and finally have a stick shift. What do you guys think i should do, any advice at all would be great.
You gotta drop the tranny. I can do a R+R in about an hour. Much practice. I think labor on the job is like 150 200 dollars and the part is like 10 go figure. If you want to get rid of the zf nows the time. Get everything driveshaft, rear end gears (center section) everything. The 700 also have the hydrolic clutch dont for get that. I think you also have to change the bushing in the crank to a bearing. All in all with tools and jackstands and a helper for some stupid stuff a weekend project. oh have fun with the bolt on top of the bellhousing. That one never goes back in my cars.
You dont really have to swap the rear end gears, just buy taller wheels and tires ;-)

Pull the trans and replace the seal, DIY and save the money, it's not that hard of a job. I'd wait for the swap until I had everything ready to install, it could take some time to gather up all the parts and expertise you will need.