Cadillac STS Forum - 2005 through 2012 Discussion, Rear differential leak again in Past Cadillac Vehicle Discussion; I think you are probably alright if the car has gone that log without trouble, but then again, if you ...
I think you are probably alright if the car has gone that log without trouble, but then again, if you did not own it, you can't be sure if it has had any problems or not. I just got my car back a few days ago from the Cadi dealer, replaced the entire rear diff this time. I would estimate the cost for an entire rear diff is around $3K. The carrier (housing) itself is $1K, not including any labor or additional parts. I think the STS is an awesome car, you can have problems with any car... yes even Mercedes, BMW, Lexus etc. I would highly recommend though that you find a cadillac certified car, mine was when I bought it last year and my warranty is good until 2012 or 100K miles, whichever comes first... that warranty is even better than what I would have received if I would have bought a brand new 2006 STS off the lot the day I bought the car.
Alright, well, I looked under my car yesterday and realized that there is an oil streak down the side of my differential and oil periodically drips down from it. Seems like I'm in the same boat. I'm hoping I can hold out until warmer days to do this repair. A few questions though: has anyone here tried tightening the bolts up a bit? That's the first thing I was going to try. Secondly, from the countless posts on this topic, it seems that the gasket between the differential casing and the cap is the weakest link. It also seems like the replacements supplied by the dealer are no good. Does anyone here know of a good aftermarket gasket or if there is any reason NOT to make your own with the red RTV stuff?
My diff was showing a small drip so I went under to take a peek. it looked like the gasket was leaking from the second bolt from the bottom on the drivers side flange. I cleaned it up to see if I could see any wash in the road dust no drip for four days then drop on floor today. when I went under today I noticed a crack in the cover where the differential flange extends to frame. I cleaned the area around the crack and used some differential rtv sealer to see if I can seal it up. I hate to think of pulling axels and diff to repair this obvious faulty part. out of warranty.