# Rear end makes popong and grinding sound



## ThatblackGTO (Oct 11, 2015)

My rear end started making a poping and grinding sound a few months ago while turning slow to the left or right so i changed the fluid with royal purple 75-140 and it said it had the additive mixed in so i used that and the sounds went away for prabably 2 month's then came back so i went to GM and got there additive and put in around 2oz and the sound is still there should i just keep puting the additive in or what


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## GotTogO (Jul 25, 2013)

I expect your differential is beginning to fail. You should look into rebuilding the limited slip or replacing it with something like the TrueTrak.

Maybe talk to rearend shop.


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## ThatblackGTO (Oct 11, 2015)

GotTogO said:


> I expect your differential is beginning to fail. You should look into rebuilding the limited slip or replacing it with something like the TrueTrak.
> 
> Maybe talk to rearend shop.


Thanks for the response and I just talked to a shop and they said try torco 85w 140 with there type f modifier first. What would be the advantage with the truetrak over the stock lsd I do plan on heads, cam ect in the future.


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## svede1212 (Nov 1, 2005)

ThatblackGTO said:


> Thanks for the response and I just talked to a shop and they said try torco 85w 140 with there type f modifier first. What would be the advantage with the truetrak over the stock lsd I do plan on heads, cam ect in the future.


They are right. Try the Torco first. With a TrueTrac you don't need friction modifier as they don't depend on slipping cones but just use regular gear oil. From people's experiences I've read though I'd get a WaveTrac. The TrueTrac seems to have had spotty reliability.


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## ThatblackGTO (Oct 11, 2015)

svede1212 said:


> ThatblackGTO said:
> 
> 
> > Thanks for the response and I just talked to a shop and they said try torco 85w 140 with there type f modifier first. What would be the advantage with the truetrak over the stock lsd I do plan on heads, cam ect in the future.
> ...


Thanks but $1,200 might be alittle much for me Lol and the torco should be in Friday if that fixes it im going to try to do something about the wheel hop thinking about drag bags to start out with.


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## svede1212 (Nov 1, 2005)

Nothing is cheap about these cars.  If it doesn't take care of it and you want to save some money look for a used diff. A TrueTrac is cheaper than a WaveTrac but with installation both are quite a bit of money.


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## ThatblackGTO (Oct 11, 2015)

That's what i was thinking just get a used 1 if its still acting up


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## randyvettes (Dec 19, 2015)

Short n sweet rear dif fluid DIY: 
https://youtu.be/ZVw-IgDOtZs


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## ThatblackGTO (Oct 11, 2015)

randyvettes said:


> Short n sweet rear dif fluid DIY:
> https://youtu.be/ZVw-IgDOtZs


Cool video and I put the torco in about 3 weeks ago and so far on made the grinding sound 1 time and it was a day or 2 after the oil change and had no weird sounds since


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