E-30 Transmission Rear Seal(s)

[Al Waschka <awaschka@xxxxxxxxxxx>]

The latest in my DIY trials and tribulations...

My daughter is taking my old 325e off to school.  While rebuilding the
PS rack (subject of a previous post) I noticed oil stains on the rear of
the transmission case. That repair has held, and the rebuilt rack is
working like a new one.   I assumed the output shaft seal was bad, and
picked one up at the dealer.  While reading about the removal, I noticed
the gear selector shaft goes in the rear so I decided to change that
seal too.  Guess what?  It was the one leaking.  Its less that an inch
in diameter and all the way up at the top of the case, but was leaking
enough to stain the whole rear of the transmission and nearby body.
When I drained the oil it was down to less than a quart.  Wasn't making
any noise, yet.

To get at these seals you have to remove the complete exhaust system,
the heat shields, drop the driveshaft and remove the transmission output
flange.  Once again, the factory repair manual provides good, complete
instructions.  The factory manual says to unbolt the rear transmission
mounting bracket from the frame and lower the transmission (tilting the
engine down to the rear) to get the driveshaft off.  The Bentley manual
doesn't mention this.  It is necessary (IMHO) to get the Guibo off the
studs.  Bently's car had bolts where my car had studs.  Speaking of the
Guibo, mine was shredded.  (Almost 100K and 13 years)  Oh, well, I'm in
there, so what's another $30 or so?

The only catch is the special tools.  The nut holding the flange on the
output shaft is a 30mm with a built-in washer.  It is recessed in the
flange.  My Bentley manual says to use a 30mm deep thinwall socket.
NOBODY and I mean NOBODY in my area had anything that would work and
that includes SNAP-ON.  Fear not, there is a solution.  At your local
parts place, buy a Leslie 30mm deep impact socket for 4WD axle nuts.
Use a bench grinder and remove about half the thickness, tapering up
about 1/2 inch on the body of the socket.  You are in business.

When replacing the flange, use some gasket sealer on the nut to seal the
area of the splines.  You are supposed to tighten the nut to 125 ft.lb,
loosen and tighten to 89.  A crowbar  between the socket and the studs
on the flange will hold the shaft from turning.  The engine turns in
reverse with less than 85 ftlb.  BMW wants you to use another special
tool, but it isn't necessary.

The job is dirty, hard unless you own a lift, but for a day's effort you
can save about $250-300.  I put the right side up on jackstands and it
wans't too bad.  While I was in there, I replace the selector shaft
coupling.  That really tightened up the linkage.  Another $9 well
spent.  Dropping the exhaust and driveshaft is a lot of work.  Replace
anything you can while you are in there.

Al Waschka
BMWCCA 104964
325e (used to be mine)
Wife's looking....

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