Is synthetic ok?
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Teching In
Joined: Jan 2013
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Is synthetic ok? I just changed the fluid in my 2000 camaro ss with mobil 1 synthetic 75 90. Then I was told not to use synthetic in the rear should I change it? The bottle said it has the limited slip additive in it already. Thanks for your help.
I just spent a bit of time looking through a bunch of old threads as I plan on doing my rear diff fluid over the winter. I narrowed my decision down to the Mobil1 75w90.
If you have a 99-02, then you're fine with the synthetic and not adding the GM limited slip fluid. However, if you have a 98 or older, then you want to avoid the synthetic and be sure to add the limited slip additive. This is because the 99-02 units use spider gears rather than friction discs like the previous years.
The only caveat to that rule would be if someone had already replaced the factory Torsen unit with an Eaton or Auburn that uses clutch discs.
If you have a 99-02, then you're fine with the synthetic and not adding the GM limited slip fluid. However, if you have a 98 or older, then you want to avoid the synthetic and be sure to add the limited slip additive. This is because the 99-02 units use spider gears rather than friction discs like the previous years.
The only caveat to that rule would be if someone had already replaced the factory Torsen unit with an Eaton or Auburn that uses clutch discs.
IMHO, no.
I dont like synthetic oil for the rear end. I had a dead quiet set of 3.90s in my 9" with 2K miles on them get totally destroyed after four passes at the strip. After the last pass and on the way home, they screamed bloody murder on accell and were still quiet on decell. Oh and I put synthetic oil in the rear just prior to going to the strip.
Nothing moved in the rear, the gears were burned up as a result of intense heat. After researching on the net, I found others who had similar issues with synthetic in the rear. No more synthetic rear gear oil in my car.
I dont like synthetic oil for the rear end. I had a dead quiet set of 3.90s in my 9" with 2K miles on them get totally destroyed after four passes at the strip. After the last pass and on the way home, they screamed bloody murder on accell and were still quiet on decell. Oh and I put synthetic oil in the rear just prior to going to the strip.
Nothing moved in the rear, the gears were burned up as a result of intense heat. After researching on the net, I found others who had similar issues with synthetic in the rear. No more synthetic rear gear oil in my car.
My local rear end shop doesn't recommend synthetic for our rears.
He says that while the synthetic DOES have better heat properties, he still prefers non synth as it seems to coat the gears better than synth. I don't know if there is any truth to it, but since I've switched to non synthetic, I have had better rear life.
He says that while the synthetic DOES have better heat properties, he still prefers non synth as it seems to coat the gears better than synth. I don't know if there is any truth to it, but since I've switched to non synthetic, I have had better rear life.
Launching!
Joined: Jul 2013
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I'm not trying to threadjack, but I just had a auburn posi diff from a '98 z28 installed in my '00 z28. According to what I've read in the past 15 minutes, I guess I used the wrong gear oil, because I went with Mobile1 Synthetic 75w-90. I did use the additive. So far, I havent noticed any noise or performance issues... I'll need new axle shafts soon, so I guess I'll have the diff fluid swapped then just to play it safe
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I put royal purple fuid in my car (98/ 10-bolt) not long ago when I did the axle swap and T/A diff cover. Not long after that my car now jerks and clunks going slow making turns. I'm thinking the royal purple had something to do with it....
You're right -- it probably did have a LOT to do with it... you've got a '98 with the Auburn clutch pack diff. Synthetic for 99-02 only.
same thing happened to me so when i put the royal purple in, i add a half bottle of gm limited slip additive and its fine. i may go back to standard fluid on my next change though.
