WTF rear diff sounsd like a treadmill set to its highest speed.
 

Ok I searched a bit but didn't find anything, probably because of my stupid way of describing it. My car at speeds above 40-50mph sounds like a treadmill cooking'er at full speed..... I think its the rear diff, anyone know what in talking about?

A loud whining noise coming from the rear end while driving? My original rear end sounded like that since the day I got it, and was still performing fine when I replaced it 25k miles later. But of course it could've failed at any time.

I would try changing the fluid first of all. Use something high quality (I like Lucas brand myself). Then start keeping an eye out for a replacement, or start saving money for a rebuild. It could last forever like that, or fail tomorrow.

In my best Clint Eastwood voice; "Are you feeling lucky punk?" :)



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Yea Ill do that and change the fluid, it all started after our first snow and the temp dropped below 15 degrees Celsius. Do you think it could also just be the cold and metal shrinkage.

I don't feel too lucky now that you mention it, Ive got a GSL-SE and all I've ever seen in NS is 2 '82 12a's

I have owned 4 1st gen RX7's and all have had a whiney rear diffs. My current mint 90,000 mile GS has a whiney diff, but I know it's fine. I think something about how the watts linkage mounts that transfers all the noise and vibrations directlty to the unibody that amplifies normal gear noise.

What does a treadmill sound like?...


Munch, munch, slurp... yes I'll have more gravy on my left-over turkey. Oh... and another butter saturated biscuit please!

I would say that , as long as you don't have a tremendous amount of slack (presenting itself in the form of bucking off throttle or clunking) take the advise of Kentetsu.

By the way, I love your I.D. pic!
"If you can't give me one reason you don't like clowns... I'll kill your entire family"

Klassik

check your u-joints first if humming starts around 30mph

Thanks guys, I really appreciate all the helpful comments. And mikliska that quote and this one "Goddamn, motherf***er got blood all over my best clown suit". make me lose it every time!

I'm surprised it hasn't been mentioned yet, but when wheel bearings wear, there will be a metallic whine. I have a bad wheel bearing on mine that I need to get to. Almost sounds like static on the radio. Certainly check your fluid, but if it persists. I'd take a look at the bearings.

if you do a lot of heavy accelerating, it could be the gear lash in the diff, is it on acceleration, deceleration, or just all the time?

thats what my rear diff did intell i replaced it.. i took it apart and the problem came to be the bearings if you want i got the new ones siting in my car still.. the plan was to fix the old diff and sell it but i never got around to it since it required a shop to press it together...let me know though

Yea its during acceleration/deceleration.

Thanks for the offer, I'm gonna try and borrow my buddies garage on the weekend and take a look at the diff and change the fluids if it persists i might as well replace the bearings preemptively rather than wait for it to happen.

If the sound is constant while performing side to side swerving manuevers, then it will be the differential.

If the sound changes while swerving, then it will be the wheel bearings.

(Good Catch bshusted) :)

The wheel bearings definitely need to be changed it was sitting since 2004, but yesterday I started getting a lot of bucking now in addition to the buzzing/humming when I lay off the gas when starting to come to a stop or when pulling away.

Could the bucking also come from old control arm bushings in the rear?

I am the only one that I have seen this happen to. My old 84 GS made a ton of noise and vibration at speed, the culprit the diff housing was cracked right at the passenger side spring perch. Hope this helps

My buddy vinnys camaro makes a god awfull high pitched whine staring at about 35-40 mph in his case its the pinnion bearing...

Yea, so, there was like 1/2 a cup of metal particle filled fluid in my rear diff and that was it. I flushed it out and refilled with SAE90. I'm wondering if I was too late......... its still making that noise maby its like what CHiNO84gsl said and its the pinnion bearing?

If you've got metal shavings, just changing the oil is not going to fix the problem. Sounds like either the pinion bearings or the carrier bearings. Maybe both.

I would pull the 3rd member (diff) and have a looksee. Better to replace a couple of bearings now than the whole diff later.

The bearings back there are hosed with that much metal in the gear oil. The pinion bearing is usually the first to go as it spins at a faster rpm than the carrier bearings.

I'd pull the 3rd and and get er rebuilt. Bearings aren't that much.