Partial throttle Rear end grumble/grinding

[Balleristic31]

So during the last few monts I've been having a wierd partial throttle grumble noise coming from my rear end. I'm guessing it is either the rear u joints on te driveshaft or my diff but I would like to get some input on what it could be.

Details on my setup:
All new poly subframe and trailing arm bushings
Medium case 4.10 LSD with fresh fluid and reseal and good condition bushing
1 new cv axle and one original
Original wheel bearings
Gcs w/ bilsteins shocks


Any ideas?

[ahlem]

Wheel bearing.

[Balleristic31]

Only reason I don't think wheel bearing is because its not a whine and it does change with loading/unloading either side of the car. Sounds like its coming from the center of the rear end as wheel.

[ELVA164]

Only thing I can think of would be the inner CV joint on the old side, assuming the diff itself was in good condition. How did the ring and pinion look?

[Todd Black 88]

I have what sounds like the same issue. Mine does not change with cornering, but completely goes away when accelerating and decelerating. I only hear it on light, coasting style throttle. No idea what it is, but I am leaning towards the input bearing on my diff, as EVERYTHING is new in the rear of my car except the diff. Could be a faulty new part, but............?

[Balleristic31]

I have what sounds like the same issue. Mine does not change with cornering, but completely goes away when accelerating and decelerating. I only hear it on light, coasting style throttle. No idea what it is, but I am leaning towards the input bearing on my diff, as EVERYTHING is new in the rear of my car except the diff. Could be a faulty new part, but............?

This is EXACTLY what I'm experiencing. The diff looked ok when I opened it up but honestly I don't remember exactly. But I am also leaning towards input bearing.

[AlphaE]

LSD???? only on very light throttle???

if its a LSD then its the clutches hanging up a little bit. Mine did the same thing. you need an additive called a "friction modifier" to put in the diff. It takes only a few onces. I used stuff we had at the shop that was for the diff's on a Lull telehandler. But i know Mopar makes a fritcion modifier as well. I put in a few ounces and that was 2 summers ago. Quite as a mouse now, no worries at all.

I did jack up the car and check the LSD breakaway tourqe (or whatever its called) and it was good. Just them clutches being funny. Its cheap and easy to try.

[Todd Black 88]

I run Redline in my diffs, and it's for LSD's and comes with friction modifiers in it.

Maybe not enough?

[Wanganstyle]

Has nothing to do with lsd friction modifier.

If there is a whining coming from differential it's going to be the pinion bearings/races dying.

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[Todd Black 88]

It's not a whining, it's a coasting throttle grumble/rumble.

Nobody said anything about a whining, not even the thread title says that.

[AlphaE]

thats exactly the noise i was hearing.. under VERY light throttle. would go away when off the gas completely or on the gas any harder.. Never used the redline stuff so IDK. But friction modifier is my vote:)

[Balleristic31]

I also use redline fluid with friction modifiers in my LSD. The noise also was not very apparent when I first swapped in the diff and new rear end stuff about 10k miles ago.

[Balleristic31]

Also just to clarify once and for all, the noise I'm experiencing basically sounds like when you here large rocks at the bottom of a river getting rolled along by the current. NOT a whining noise at all.

[Wanganstyle]

Post a video or sound clip of the actual noise; its pointless to talk about sounds. LOL