The last time my car was at BMW for service, my advisor told me that my rear differential bushing is starting to crack. I didn’t think it was that serious. It’s a rubber bushing. I even had one of my guys put my car on a lift to see how bad the crack was, it was barely enough to even call it a crack. A few techs even told me, it’s not a big deal, you can still drive on it for a while. You’ll start to feel it, and/or hear noises when it really needs to be replaced.
And then this happens. I’m on my way to work, and my car stops accelerating. Luckily I wasn’t too far from home, and the car still went about 5 MPH, so I was able to get back home.
The rear differential bushing is literally, a rubber bushing. I would have never thought that this bushing can stop my car from accelerating. I expected it to maybe make the ride noisy or rough. Or even make the acceleration rough, but not make the car not accelerate altogether because of a little crack in the corner of the rubber bushing.
The best part of this? BMW has to do the install. A few tech friends didn’t want to touch it. We even drove the car to L.A because a mechanic that my sister works with was willing to do it for us, but once he got my car up in the air, he declined to do it. It turns out pretty much everything in the rear of my car has to be taken off (Suspension, Exhausts, sub-frame, etc) and even after that, you need a special tool that BMW has, or a press, to get the bushing on the rear differential. BMW originally asked for close to $2,000, however we were able to bring it down to under a thousand dollars.
If i think about it now, there were some warning signs before the dealer even told us about the crack in the bushing. There were a few times when accelerating, it sort of felt like the transmission was slipping, and the car sort of stalled before speeding up. After that, my RPM’s seemed higher than usual whenever I start the ignition. Again, I never knew this bushing can be so important to the car. I read on some forums that some people replace this bushing at 50,000 miles. For us, we put over 100,000 miles on our car before running into this issue, so I’m sure it will have to do with the way you drive too.
The funnier thing about this rear differential bushing issue, is the fact that after everything, and when the tow truck arrived, the car was acting fine again. Regardless, we had the bushing replaced today, and the car feels a lot smoother. The dealership also gave us a 2 year, unlimited mile warranty on the repair. When this first happened to us, I tried to research forums, and Google this issue, but wasn’t really able to find out how serious this issue is. So here, take it from me. Do no take this issue lightly. I would hate to see anyone stuck in the middle of nowhere. It does not have to be replaced right away, however do not go for too long. I think we drove a good 5000 from the moment we found the issue, until the car actually stopped accelerating like this. =)