View Full Version : Rear Diff. Noise
Hey Guys,
I need your help in diagnosing this thing.
First of all, I'm going to assume the noise IS indeed coming from the differential.
It's kind of a grumbling noise when I first back up (or even ease forward and turn slightly). It doesn't happen every time -I'd say roughly 85% of the time- and once I get going it rides smoothly.
Now, according to my spid I've got a G80 (limited slip diff.) -do those things have clutches of some sort to help it lock up?
What happens when they start to go out?
Also, what do rear axle bearings sound like when they start to go out?
I've never had any go out on me, but I would assume that they will eventually.
Any input on this would be GREATLY appreciated. (My books aren't any help.)
Try adding GM limited slip additive to the differential fluid. It helps in most cases of rear noise at low speed with stock auburn lsd.
Lucas makes good stuff. I've only used the motor oil additive and the power steering fluid additive but they work great. My neighbor who is a mechanic swears by all their stuff so i would give that a try.
Originally posted by 9C1LT195
Try adding GM limited slip additive to the differential fluid. It helps in most cases of rear noise at low speed with stock auburn lsd.
would that help with eaton lsp?
Yes. You HAVE to add limited slip for any clutch based limited slip differential (includes auburn, eaton, traction-lok, etc...) On the other hand, torsen based lsd's (use worm gears, no clutches) do not need any additives and do not wear out. That is the reason I've got Torsen T2.
Tell me more about the Torsen diff.
Where did you get it?
Do you have to change the housing, or will the unit fit in the original housing?
What's the average cost for that type of diff.?
What kind of ratio do you have?
Thanks for the tip, ya'll.
I put limited slip additive in and I haven't heard that noise since.
It made a world of difference.
I just knew I was going to have to replace the differential.
(or rear axle bearings)
where did you get that additive? :)
how much was it?
Oh man, that stuff wasn't but about $3.50 (I think it was a little less).
It came in a plastic tube and was as thin as water (that kind of concerned me).
It said drain all the oil out, put this stuff in -all of it- then top off with the recommended oil.
It's simply amazing. My diff. was making a growling/grinding noise and sent a grinding vibration through the car when I backed up (or pulled forward while turning slightly).
I waited a week before I posted the results, lest I recommend the oil then my differential blow up.
Oh, and I got it at AutoZone, but I imagine PepBoys has it as well.
autozone it is.
thanks for the help. i'm about to drain my rear for the fine tuning of the 4.10's which whine like a freaken unbalanced bus wheel or something at times.
i'll def use the fluid
thanks alot.
Originally posted by LM13
autozone it is.
thanks for the help. i'm about to drain my rear for the fine tuning of the 4.10's which whine like a freaken unbalanced bus wheel or something at times.
i'll def use the fluid
thanks alot.
LM, get a GM or FORD limited slip additive from a dealer. I've had noise problems with my factory differential. Those will work the best. The aftermarket additives weren't able to quiet it completely. I assume the same applies for Eaton.
P.S. This will only work if your differential grinds at low speed or/and reverse. Gear whining means that either the pinion gear was not spaced correctly or the backlashing is set wrong. If you drive more than 50 miles or so, the chances are that you won't be able to fix the wrong wear pattern.
Originally posted by 9C1LT195
LM, get a GM or FORD limited slip additive from a dealer. I've had noise problems with my factory differential. Those will work the best. The aftermarket additives weren't able to quiet it completely. I assume the same applies for Eaton.
P.S. This will only work if your differential grinds at low speed or/and reverse. Gear whining means that either the pinion gear was not spaced correctly or the backlashing is set wrong. If you drive more than 50 miles or so, the chances are that you won't be able to fix the wrong wear pattern.
so what you saying that it will never stop whining?
Originally posted by LM13
so what you saying that it will never stop whining?
Unfortunately, yes. It can probably be reduced but not stopped. Can you describe when the gear whining happens (acceleration, deceleration, steady speed, at what speed ranges)?
Originally posted by 9C1LT195
Unfortunately, yes. It can probably be reduced but not stopped. Can you describe when the gear whining happens (acceleration, deceleration, steady speed, at what speed ranges)?
it is usually there when i just cruise(not accelerating or slowing down, but it does tend to get more noticeable when i start slowing down), and the rear is nice and hot.
it ain't that bad of a whine, i know that it is there coz i listed to that kinda of stuff, i'm putting it on the lift tomorrow to try to get everything adjusted right.
now i can live with the whine just like i can live with the drone. the only thing i'm worried about is that is it dangerous for the rear, aren't the chances of my pinion blowing increase coz of the whine?
i personally think we'll be able to remove it.
Whine on deceleration is usually not dangerous for the rear. My gears also whine slightly from about 50 to 40 mph. It will get a little better when the gear break in. However, if the noise does not disappear when you put your foot on the gas, there is a problem with your gears.
BTW how is traction with 4.10's? :)
Originally posted by 9C1LT195
BTW how is traction with 4.10's? :)
I can answer this one for Lenchik having driven his car: what's tracktion? ;)
Originally posted by 9C1LT195
Whine on deceleration is usually not dangerous for the rear. My gears also whine slightly from about 50 to 40 mph. It will get a little better when the gear break in. However, if the noise does not disappear when you put your foot on the gas, there is a problem with your gears.
BTW how is traction with 4.10's? :)
thank god there is no noise when i put the pedal to the metal. also the traction magically disappears. and you start going sideways alot.
thanks for you help dima i hope tomorrow they'll straghten the whine out.
btw i cant wait to see your 1/4 mile times.
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