Drivetrain Increased axle noise with urethane control arms bushings?

boostfrk said:

Sharad - Thanks for the offer man, I really appreciate it. I'm in north/esat central FL. West Palm is about 3 hours south of me and Ft. Myers is closer to 4 or 5.

I recently switched rear ends (complete rear end swap) and the rear end I swapped in had the poly bushings in the upper housing above the pumpkin. So, I went to a rear end that I don't know the exact condition of and poly bushings in the differential housings; hard to say which one is the culprit since I introduced 2 variables at once. It could be either. I figure since it's easier and cheaper to replace the differential housing bushings, and a good idea anyways, I'll start there and see what happens. If the noise is still present I'll dig deeper and start to suspect some issue with the rear end.

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boostfrk said:

So I've replaced both upper and lower control arms with UPR's chrome-moly arms with urethane bushings; the rear differential housing does have the urethane bushings as well but those are getting changed out for replacement OEM style rubber bushings in the next week or two. I'm hoping that helps this issue.

This is a street driven car, no track time, and generally driven pretty easy on the streets.

I can hear what I believe to be the axles turning in the rear end, and it's not quiet. It's a noise that is speed dependant. It's not really a grinding, or a whine, but more of a rubbing sound. Axle bearings and seals are brand new and axles have nearly no pitting or scaring. Fluid is brand new with Motorcraft friction modifier.

Is it normal with urethane control arm bushings to hear an increase in rear end noise in the cabin? Is this just part of having a solid axle RWD car that's 23 years old? Is there anything I can do, or at least anything to reduce the amount of noise transmitted into the cabin?

I hate noises like this...

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1200gt said:

Boostfrk,

did you finally figure out what the problem was with this noise? I'm pooling data and considering to Urethane/Poly or NOT. I'm street driven too - no track.

You can read some many opinions on this stuff til you get dizzy from all the yes yes yes , no no no's!

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ratio411 said:

It's a bit off topic, but you guys running non-rubber bushings in the upper arm mounts, the ones on top of the 8.8", do they help with wheel hop?
Our Fox body Fairmont has tremendous wheel hop since it does not have quads.
All of our suspension bushings throughout the car are poly, except the stock rubber bushings on top of the rear end.
It has the tubular upper and lower control arms, non-adjustable, GT Mustang rear sway bar, new stock replacement coil springs w/poly isos, and Moser girdle on the rear. 4.10 gears and stock TL unit...
Any ideas on stopping wheel hop?

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RangerJoe said:

I just swapped to adjustable uppers a few months back and had the mechanic set my pinion angle while he was going over my 4.10 swap. After he threw in some negative angle, I started have horrible wheel hop. Not so much from a dead start, but more from a roll then punching it (I'm on 555R's). I stiffened up my rear Strange shocks (like an 8 setting) and it helped tremendously. However, last night I was coming home around 3:00am and we have had a cold snap (about 40 degrees). I punched it from a roll and about knocked my fillings out from all the axle hop. I think the cold tires and pavement just make it worse. I will eventually put a fresh set of quad shocks back on. Unforetunately, I think this is the only permenant solution, except perhaps a completely redesigned rear suspension. Oh yeah, I have all poly pieces, even the 8.8 housing.

Joe

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