rear differential popping noise

[TruDom]

12 bolt limited slip differential. no noise or issues when diff is cold or driving straight. will get a popping noise when making a sharp turn after say a 30 minute drive.

its done this since i've owned it. I did replace axles to 5 lug pattern and put in masterpro 80/90 GL-5 gear oil, filled to plug hole.
Do i have too much or not enough oil?
Are the clutches just worn?
any additives to help?
are my limited slip springs just worn now?
ideas?

reiterate that it is a popping/ratcheting type noise and not a constant grinding.

thanks!

[FirstOwner69]

Try adding some GM friction modifier for posi axles. But, don't overfill.

[Mbeef61]

Is it a posi? Or other LSD?

[100%Chevy]

I have it in my 68.
I tried everything suggested and still no relief!
Finally,I was told to drive it more.
I only put about 200 miles a year on it,so that has to be the problem.
Now,I just live with it.It ain't broke in the 11 years I've owned it (so far).
Mike.

[truck-kid]

i agree with adding gm posi additive and then drive a few miles to mix it into the oil.Then go to a parking lot and make 8-10 tight circles to the left and then to the right to work additive lnto clutches. This cured numerous posi units making similar noises for me when i worked in a repair shop in the 80`s.

[Steeveedee]

^^^That right there, though I used to use a Sta-Lube product. Those left and right turns make certain that the lube gets to where it is needed sooner. Plus, there might be a tire roasting video in our future?

[ohboy321]

It is possible that there is a damaged clutch/plate. Picture below is what I found when took mine apart. Obviously mine was a total failure, but a clicking sound when turning could be because of some issue with the clutch/plates.

I drove it for a couple of years like this, and didn't even know it was a posi until I pulled the cover to change the fluid....and had pieces drop out! Lucky for me there was no other damage. Installed a new clutch kit and it works great now.

[TruDom]

Thanks everyone. I'll try the gm posi additive

[csolomon71]

Im having the same issue on my 71 c10. Ill have to try that too. I'll let you know if it fix's my problem as well.

[TruDom]

put the additive in... admittedly only got maybe 3oz in. had some left in bottle and leakage. should have pumped more oil out before.

It did improve it a lot. Its only made the pop noise a couple times since. will drive more and see if it still happens and add another bottle.

thanks everyone.

[Frank_Zappa]

My 71 K/20 makes a noise anywhere from a popping sound to a major BANG from the rear end sometimes. I have learned to just accept it. My rear end is the Eaton HO52 with factory No-Spin traction control. I think it is a broken spring in the unit but not worth going in there to fix it unless catastrophic failure happens, which I have been told it probably won't. Knock on wood.

[Chilly178]

Originally Posted by Frank_Zappa

My 71 K/20 makes a noise anywhere from a popping sound to a major BANG from the rear end sometimes. I have learned to just accept it. My rear end is the Eaton HO52 with factory No-Spin traction control. I think it is a broken spring in the unit but not worth going in there to fix it unless catastrophic failure happens, which I have been told it probably won't. Knock on wood.

My 72 C20 has the same axle and it does the same thing. I don't believe they are broke its just how the detroit locker works. https://www.eaton.com/Eaton/Products...ials/index.htm Also no posi additive is needed in a Eaton no spin.

[74Corvette]

Originally Posted by TruDom

12 bolt limited slip differential. no noise or issues when diff is cold or driving straight. will get a popping noise when making a sharp turn after say a 30 minute drive.

its done this since i've owned it. I did replace axles to 5 lug pattern and put in masterpro 80/90 GL-5 gear oil, filled to plug hole.
Do i have too much or not enough oil?
Are the clutches just worn?
any additives to help?
are my limited slip springs just worn now?
ideas?

reiterate that it is a popping/ratcheting type noise and not a constant grinding.

thanks!

Sounds like classic LSD clutch chatter to me. They will chatter more once the diff warms up. Crack open the rear cover, check the clutches the best you can for damage. If it looks ok fill it back up, but first add two bottles of the ac delco additive before adding the oil. This stuff is the best for this. After the diff is warm go do a bunch of circles in an empty parking lot. I had the same issue and this stuff got her purring.

https://www.summitracing.com/int/par...4003/overview/