is leaking... I need to replace it as well as drain out the old fluid and put some new fluid in.... So now my question:

Where can I can get a quality rear transmission seal?

And I'm assuming some kind of Castrol/BMW gear oil is the recommended oil

Thank you

http://www.autozone.com/selectedZip,78404/initialAction,partProductDetail/initialpartType,00074/initialR,APP125611/initialvehicleId,1190601/shopping/selectZip.htm

Autozone stocks them. And I just went with 80W gear oil IIRC and have had no problems. The seal is a breeze to install.

1) Put all four corners of car on jack stands and drain fluid

2) Remove drive shaft to transmission bolts

3) Remove driveshaft center bearing mount nuts

4) Drop the guibo out from between the shaft and tranny

5) Remove 30mm output shaft nut

6) Remove output shaft flange (you may need a puller..... I did not)

7) Remove old seal

8) Put everything back together.

9) Refill with gear oil

Only problems I ran into were the output shaft nut must have been torqued on by the Hulk to like 9K ft/lbs and I didnt have a allen key big enough for the drain or fill plugs.

To overcome this I let the breaker bar rest against the body of the car and bumped the starter a couple of times and for the plugs I used a bolt that had a big enough head on it and welded a nut to it so i could put a wrench on it.



Hope all this helps...

haha, he calls it a breeze.... well if you're the first person to take apart your driveline in 25 years, you're going to make your own breeze by the time you've finished getting all those driveshaft bolts off

also, bavauto sells a really expensive 17mm hex socket for the tranny oil drain and fill plugs. they are really hard to find anywhere else, but if you look hard enough, they can be had.

also:
I couldn't find a socket to fit the nut on the transmission output shaft. nobody made a normal thickness 30mm socket, they were all heavy duty impact sockets that wouldn't fit into the deep-set hole where the nut is. so I took a 30-mm CR-MO impact socket and turned the end down so it would fit. I have no more use for it, (knock on wood) so its yours for $30. (the socket itself cost $24) pics coming in a few.

trev

I really didnt have much of a problem with it. And yeah you will need a 30mm deep thin wall socket I bought mine at a tool specialty shop

I had to turn a socket as well. The drain plug keys are by no means hard to find, you can buy a 3 piece set at autozone for $10. Make sure your gear oil does not say EP or extreme pressure. That is far more important than what weight you put in. I recommend the Redline MTL, but if you want to know a secret I'm actually running a mix of synthetic Lucas (way overpriced) and ATF. Straight ATF is good for frigid climates. I stress it again and again because I have had nothing but trouble trying to find a non EP gear oil. Make absolutely sure its not EP. This is why you should just order the Redline and not have to worry about it.

come to think of it im not totally sure that I didnt use EP. What kind of problems will arise?

Burned syncronizers. EP means there are micro 'sponges' in the oil to keep it from getting squeezed out from between gears. Squeezing the oil out is exactly how a syncronizer operates. If the oil can't get out, the syncro can't work, and will overheat and be damaged.

is leaking... I need to replace it as well as drain out the old fluid and put some new fluid in.... So now my question:

Where can I can get a quality rear transmission seal?

And I'm assuming some kind of Castrol/BMW gear oil is the recommended oil

Thank you

You didn't mention weather or not you are dropping the transmission. If you are, you can basicly re-seal the tranny. The biggest leak comes from the selector shaft seal. As always, something that costs pennies causes the biggest mess! Make sure that it is the output shaft seal that's leaking because the selector seal can leak straight down onto the output shaft and cloud the real souce. The output shaft seal is a bitch, and I bought the special tool from bav auto (30mm thin wall socket) to take off the nut! The first one was taken off by an independant BMW shop. It broke his socket. He used map gas to heat it up, and even then it took 45min. He bent the output flange with his puller before it broke loose! The second one I did came off ok after heating with map gas and my socket+air tool.

The input shaft seal is much easier, and if you are taking the tranny out, worth replacing.

Good luck!
John

The second one I did came off ok after heating with map gas and my socket+air tool.

The input shaft seal is much easier, and if you are taking the tranny out, worth replacing.

Good luck!
John

LOL! I love air tools!

Thanks for the reminder guys! Duh, I should be buying seals for new tranny before I put it in....

And +1 on Redline MTL, 1.5qts IIRC? While you're picking it up and thinking about it, have the car up on stands anyway, etc, why not pick up a quart of Redline 75W90 (http://www.redlineoil.com/products_gearlubricants.asp) and treat your diff to some new juice. I mean c'mon, when was the last time it was changed?

awesome... thanks for the help.

I am interested in that socket if your not needing it anymore...

Here is the pic. send me a PM if you want to buy it.

http://i18.photobucket.com/albums/b111/trevakills/selling/DSC02784.jpg