whats the deal - final drive problems

[chris_e34]

http://www.realoem.com/bmw/partgrp.do?model=HD23&mospid=47408&hg=33&fg=10

my automatic 535 was hit by a drunk driver while it was parked on the street. The output shaft was forced out of the rear axle drive unit. Somehow it was not bent. I replaced the trailing arm which was completely bent, and various other suspension parts. When I finally got everything back together I popped it in reverse, made a funny squeaking noise, got out of my driveway and put it in drive. The car rolled a few feet than started to coast. I gave it a bit of gas and was able to turn the car around then it wouldn’t move at all. The car acts as if it’s in neutral, when it’s in drive, with the exception that it makes a loud grinding noise. I believe the cause to be the final drive unit spinning freely, with the output shaft staying stationary. The output shaft is secure it doesn’t slip out unless I unbolt it. I would really appreciate some ideas, im going crazy

[mholbrook]

I don't know where you are at, but I have a 3.46 open diff just out of my 535. Might be a good cheap swap for your unit if you need one. Sounds like the hit ruined the diff. Insurance should pay for that too if they covered damage to your car.

[chris_e34]

i bought the car as a body and interior parts car, and has turned into a project car. the frame is trahsed so im trying not to put money into it. basicaly using it as a learning experience. just curious, how much do you want for the diff? after a bit more troubleshooting i may consider your offer.

[joshua43214]

Have some one look under the car while you put it in drive and see if the drive shaft is spinning, then see if one of the axles is spinning.

Careful you dont run over the head of your assistant...

[chris_e34]

yea, when i pulled it into my driveway i looked under the car and the driveshaft was spinning. im leaning twoards #5 on this diagram http://www.realoem.com/bmw/showparts.do?model=HD23&mospid=47408&btnr=33_0473&hg=33&fg=10

i have the rear on stands, and the passenger side wheel spins fine. the drivers side is intermediate, sporadic at times. i apreciate the info so far, anybody dealt with these bearings before?? or had similar issues? should i try another diff?

[632 Regal]

i played with differentials before http://www.bimmer.info/~regal632/rearend.html

is that flange all the way in? soulds like it isnt.

[joshua43214]

yea, when i pulled it into my driveway i looked under the car and the driveshaft was spinning. im leaning twoards #5 on this diagram http://www.realoem.com/bmw/showparts.do?model=HD23&mospid=47408&btnr=33_0473&hg=33&fg=10

i have the rear on stands, and the passenger side wheel spins fine. the drivers side is intermediate, sporadic at times. i apreciate the info so far, anybody dealt with these bearings before?? or had similar issues? should i try another diff?

If the driveshaft is spinning, but no power is going to the wheels, it won't be something as simple as #5 since that is just a bearing.

Does either axle flange spin when the wheels are on the ground? It doens't do any good to check when the wheels are raised. You need to check this this just to make sure the splines on one of axles is striped. So if lets say, the right hand flange turns, but not the axle,then the inner CV join has a striped spline. If neither axle flang spins, but the drivshaft does, something inside the final drive is broken, and you will probably do best by getting a comeplete used unit.