what diff oil???
oil do yuo have for my Z28 and he tell me get the ac delco diff oil , its true??? im running my stock diff w/o posi. whats your recomendation i dont want a noise in my diff.
Amsoil or Mobil 1, I use Mobil 1 75W90 myself, plus the GM LSD additive.
I just went round and round with this last month. Owner's manual on my '01 F-Body says: Use Synthetic along with Additive. After reading that "white paper" Fluid comparisons, also.
Btw, the EATON instructions do not support synthetic fluid's, but I called Eaton's Techline because they don't promote any synthetics.
In chatting with tech support, I feel it's due to just there being too many with Synthetic offerings with different ingredients and usefulness. But I understood the guy very well when I asked about AMSOIL and the AMSOIL "Slip Lock" additive.
He said, "put it in the rear,and if you have any chatter take it out".
I also got word from a 20 year Driveline Tech who has been using AMSOIL for 4+ years now without issue.
If you're using anything that the factory offered such as the Torsen or Auburn, Gov-Lok, you're good. You also can check your owner's manual to see the same as I did if you still have it.(To use GM Synthetic/GM additive).
It's in now for a about 250 miles and "it's all good". Quiet & smooth including a trip to the Dragstrip.
Bottom Line is that you're non posi, so go less expensive if there is a big difference.
Best regards!
Last edited by RapidRick; Nov 30, 2009 at 06:56 AM.
If I'm not mistaken, the Auburn LSD didn't like the synthetic too much (too slippery for the clutches) and needed the friction modifier additive. The Torsen unit is fine with synthetic and doesn't need the friction modifier additive since it is gear-driven, not clutch-based, so the friction modifier wouldn't be any good there.
Correct me if I'm wrong. I just got a torsen rear end, and have some basic Valvoline 80W-90 non-synthetic gear oil with no additive. Seems to be working just fine.
Here is what i used:
Valvoline no syn 85w90 - 2 qts
GM LSD Fluid - 4oz
FelPro rear diff gasket
small bead of black RTV silicone
Break all the 10 bolts loose, then pull the bottom 3 out and the oil will start to drain. Once drained out take all the bolts out, clean the inside with brake cleaner. Make sure to get it all out.
When you go to fill it back up, you will need a 3/8" ratchet ONLY. there is a little bolt you need to break loose. It is on the passanger side.
Very easy job to do
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to the OP...just regular stinky non syn gear oil like 80w-90 is all you need.
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Hope this helps.
Having originally seen that the Owners manual from my car says to use Synthetic & Additive to the rearend diff. (GM of course, I guess since it's a GM sponsered booklet). I went and investigated further, due to my replacing my original "clunking" bad TORSEN unit with an EATON carbon clutch type unit.
Then knowing some F-Bodies came with the lesser GM "GOV-LOK" clutch type Eaton units as I mentioned in an earlier post, I researched, including with two longtime builder's happily using AMSOIL for years in these units. (This even tho the EATON units instructions warn against this.
Now I was still confused so lastly, I then called EATON from one of their website listed phone numbers. I called it and was given another phone # for their Tech-Line.
Basically what I got from my inquiry with Tech Support Rep regarding EATON not reccomending Synthetic Fluid was:
"There's too many synthetics out there, and so due to inconsistancy of result EATON does not recco any.
When I mentioned I wanted to use AMSOIL & the AMSOIL Additive based on a couple of Drivetrain Longtime rebuilder's who have successfully combined Amsoil with their Carbon & Clutch type Posi's I was told:
"Well if you're using Amsoil, take it out if you encounter any problems. Chatter, etc."
I've since had it in my car with no issues, noise or problems even at the track so far, and I race this car in a Challenge Series at our local strip that averages one date per month. Just sharing what I went thru to understand why synthetic was frowned upon by EATON for my situation.
An interesting annecdote:
I was tuning up my old John Deere gas tractor, and in the process my old dwell/tach took a dump. Off I go to AZ to see if they have one. The young man behind the counter had this deer in the headlights look at the mention of 'dwell'. He thought I just wanted a tachometer. Amazingly, they did have a dwell tach, and the plastic clamshell packaging was so old that it had turned yellow from age. Worked ok, though.






