Z3 rear diff mount issues

I am currently building a 99 Z3 for the wife. The car was given to me as payment for some work did for the owner. The issue is the car was in a wreck, it was hit on the driver side rear quarter. I found a parts car for cheap and have most of what I need to fix the car. I will be swapping the rear diff assembly from the parts car as the lower control arm on mine was bent. I have both assemblies out and the diff I will be installing at the local BMW shop being inspected before installation.

The big question I have is the diff mount is starting to split. The only place splitting is where the third member bolts to the body, I do not see any other stress cracks in the body. I understand this is a common issue and there are kits out there to reinforce this area. Can anybody suggest a good kit to go with? I've looked at several sites and not found anything as of yet, I think UUC makes one?

The original diff had 3:15 gears in it and the new rear has 4:10 gears since it was an auto. It should make for a fun car to drive when I is done! Thanks in advance for the info.

I'm not up on rear axle ratios, but 4.10 sounds like it could be from a 4 cylinder car. I would wonder about the strength of that differential for a 6 cylinder car...Randy Forbes, who visits these pages regularly is the guy to answer your differential mount question

Originally Posted by ZEEBOY

I'm not up on rear axle ratios, but 4.10 sounds like it could be from a 4 cylinder car. I would wonder about the strength of that differential for a 6 cylinder car...Randy Forbes, who visits these pages regularly is the guy to answer your differential mount question

Actually the rear came out of a 2.8 auto car so it should handle what my 2.5 can give it.

erandyforbes@aol.com



Here's a link to the album of this forums' moderator's 3.0 Coupe. You'd want to do a similar repair on the car you're building for your wife: http://www.spcarsplus.com/gallery3/index.php/LZ_02

TBuff, that is good to hear that it is from a six cylinder car...be prepared for your highway/interstate rpms to go up @25% and your gas mileage to go down some....

Originally Posted by TBuff

Can anybody suggest a good kit to go with?

I would go with Randy's. See his post above.

I've been in contact with Randy. That is a very nice kit he offers. I already have the rear of the care completely stripped so no "real" extra work to install it.

I am not really concerned with the extra RPMs or loss of milage. This will be a weekend toy to enjoy instead of a daily driver. She is excited about having some spirited 0 to 60 fun or enjoying a spin down the Blue Ridge Parkway.