Differential Noise After Installing New Bushings

[jms16v]

I just installed new AKG (all urethane) rear subframe bushings, RTABs, Diff bushing, and transmission mounts.

Now my differential is making a very loud constant noise while the car is moving. The differential was not making any noise prior to the bushing install.

Is the added stiffness of the new urethane bushings the cause?

Has anyone else experienced this? Any help is appreciated. Thanks.

[bmwman91]

Yup, that's the trade-off with poly ones. I am actually going to be installing OEM rubber ones this weekend, 5 years of poly has been more than enough. I road trip a lot more than I autoX these days, so byebye poly! I still remember the difference in noise after I swapped them.....

[jlevie]

The odds are that the new bushing didn't cause the differential to start making noise. But rather that they transmit noise from the differential into the car.

[nando]

I noticed this too, but i think my driveshaft may just be out of balance. the 75D bushing is pretty dang stiff, I like the way it feels now, I just don't like the noise at 70mph.

I've had another brand of poly diff/subframe/TA bushings in my car for about 6 years, and it wasn't ever loud or harsh, but the old poly diff bushing was quite soft and let the diff/subframe move quite a bit. I'm thinking the stock rubber bushing would be best, I should have just left it alone all those years ago. Oh well, live and learn. :)

It is definitely better with the new wheels though, and it was unbearable with my old KDWs,