Rear end noise after new bushings - HELP

[lemansguy]

Hey everyone, hoping someone can shed some light on my issue. i installed condor speed subframe, rtab, and dif mount bushings. now while driving, i have a constant noise/whine coming from the back end of the car. my rear end was silent before this instal. ive read where some people have experienced more noise because of removing rubber bushings which isolate noise, but this is loud enough that on the highway i can hear the sound bouncing off the jersey barriers. ive crawled everywhere under the car and i cant find anything rubbing, but thats almost what it sounds like. ive also checked the emergency brake, cuz i thought maybe it was dragging but that also wasnt it. The sound does not vary with RPM, just speed. it also doesnt matter if i put a load on the car or not, meaning, if i get on the gas at 50 or let off the gas at 50, the sound does not vary at all. there doesnt seem to be any sort of vibration either.

any area i should check first? again i had zero noise coming from the rear of the car.

thanks

[LJ851]

Differentials make a lot of noise. Your new, hard bushings now transmit that into the body of the car cause it to resonate. There is a reason road cars have rubber bushings.

[lemansguy]

ive ridden in solid bushing cars before, and my 98 camaro had poly bushings, never had this issue. Maybe its because my other cars had solid rear axles? Oh well, if this is hwo its gonna be maybe i need a louder exhaust to help drown it out.

[ahlem]

Check to be sure your backing plates aren't rubbing on your rotors. They bend easily.

[2mAn]

Bumping this back up.

My rear end is also squeaky now since I added Poly for the trailing arms, subframe mounts and also the diff. Would using rubber on the trailing arms be the best way to quiet it down? Do I need to do the diff also?

I tried to use the best "street" setup but it seems the Poly 85A is streetable for firmness, but the noise is quite annoying.

I was told I can spray some silicon and that should quiet it down.

Anything else I can try if this doesnt work???

[estoguy]

If your car is mostly DD, I'd go rubber. I did a lot of research into this before I did my subframe and RTABs last year. The consensus I noticed is that for DD, rubber is the way to go. If your bushings are shot, new rubber makes all the difference.

[lemansguy]

FWIW ive got close to 5k miles since i replaced all the rubber with condor mounts. i replaced the dif bushing, subframe bushings and rtabs. i still hear a whine in the rear, but i don't notice it much anymore. my rear has not squeaked once since i installed the bushings, and the rear is much more planted and feels so much more solid now than it did before. i drive my e30 almost daily, and i have no issues with the "harsher" ride. i think it rides better now than it did with my nasty, worn out, rotten, rubber bushings. bumps in the road are now predictable, and i know any flexing that is happening is through my springs and shocks only, and not the subframe itself. i love my condor mounts and would do it again if i got another e30.