-T-

iTrader: (2)

What are you guys using for differential fluid? Any additive's? Estimated cost?

I have read about Mobil 1 and Amsoil but still unsure if additives are required with either. Insight is appreciated.

shadyLS6

Amsoil Severe Gear 75W-90 with no LSD additive... no chattering Apparently you never have to change the stock fluid but I did for the piece of mind after the break in miles on the diff.. i think it was 2 quarts of fluid less then 50$

Stock stuff smells like grape drank.. delicious i believe its composed of water, sugar, and purple

07CTS-V

iTrader: (6)

Amsoil doesn't require the additive, but it doesn't hurt to put a bottle of it in also. Some people have reported having to add a bottle. I add it anyhow.

-T-

iTrader: (2)

grape drank? "syrup"???

Which additive are you guys referring to? Collectively, the required gear oil is 75W-90. And the LSD additive can only help matters. Is there a specific additive for our diff's?

shadyLS6

GM has a Specific additive for the OEM grape fluid but after market additive will work as well.. just make sure you put the additive in first then the fluid..

75W-90 is stock... so thats what i used...some guys even go with a heavier weight to quiet down the diff.

gpkid16

iTrader: (1)

I've had Amsoil with GM friction modifier in my WS6 diff for the last 2 summers with no issues.

DrSpeed

iTrader: (4)

Friction modifiers reduce the grabbiness of the clutch packs in the rear end.

Add too much, it renders the clutch packs useless in the LSD....essentially making it an open rear end.

Nearly all synthetic gear oils already have friction modifiers in their "syrup."

JNR_Design

iTrader: (3)

I went with Mobil1 and some LSD additive they had at store and it works good. I'll probably change it again soon, but not sure which type I'll go with. I've ran Royal Purple in a couple vehicles and while people swear by it, I do not like the stuff, and while it claimed to have additive built in, I had to add some anyway. I've personally never had good luck running any fluid 'straight' (despite claims it contained additive built-in) and always required the additive, although sounds like some do indeed work.

We're lucky that we don't have Jeep diffs. I had an electronic locking diff (front) and wow was that thing sensitive. The generic stuff they sell did not work and ended up having to go to the dealer for the chrysler stuff. Surprisingly it wasn't that much money, so i'm gonna pick up some LSD additive from GM dealer I think, just to be on the safe side, fwiw (nothing like wasting all that money on syn fluid, lol)...

liqidvenom

iTrader: (2)

anyone go with a heavier fluid?

Stepside

I've read of some guys using a 50/50 mix.
Good question for the hot climate guys.

Does any one have any experience with Lucas or Lucas Oil Additive??
They advertise that their Oil Additive can be used in engine, trans, & Diff.
Hmmm . .

JNR_Design

iTrader: (3)

I've used lucas as a 1 qt supplement to my engine oil and didn't notice anything different than when I used any other kind of additive. Now, what I'm supposed to notice, who knows (lol), but it was on such a blowout sale I decided to try it; only thing that sucks about having 6 qt capacity is the big jugs or specials on mobil 1, for instance, only include 5 qts. and damned if I'm gonna pay full price for one quart

As for the diff, I personally won't substitute it there, mainly cause the syn oil is not super expensive and usually get plenty by buying 2 bottles (forgot the capacity of diff).

To add to my previous post, I have not tried amsoil (a little skeptical to claims), but I have heard really good things about redline and I may try that coming up. I have a quiet rearend and like to keep it that way For reference, my '06 GTO was supposed to be notorious for whiny rearends, but I never experienced it there either (bought new to 68k miles). I think the most important thing, besides not abusing your car, is frequent oil changes to a quality fluid (eg Mobil 1, Castrol syn, etc.); I've tried many different ones with many different vehicles (incl 4x4's) and never noticed much difference between any of them, except for price.

ecotec88fiero

GM specs the 75w90 grape scented stuff and tells you to add a separate friction modifier.

A few years ago there was TSB for all G80 rear diffs making groaning noises and chattering due to degraded LSD modifier.
They came out with a new fluid that had a modifier already added in that doesn't degrade with heat as much as the old stuff did. It fixes noisy clutch plates every time due to either overheating or cars sitting for long periods of time(garage queens).
Its called Dexron LS gear oil 75w90.

I have put it in a few V's for customers and so far so good.

Truely any real quality GL5 gear oil with the right modifier will work fine, I have good experience with Mobil1 stuff as well.

smbstyle

iTrader: (1)

just put in AMSOIL 75w90 SVG about 20 minutes ago, along with AMSOIL ATF in the tranny. Car seems to shift a bit smoother from the initial drive. The stock fluid in the diff was BLACK with some metallic crud on the drain plug magnet, and the trans fluid was black as well. Car has 58k and it looks like this was the first fluid change for the diff and trans, and I've had 1 track day and 10 autocross events with the car, OEM diff, no whine or anything.

I havent heard one negative review on AMSOIL, so i figured I'd give it a try.

Slithering_Joe

Since the Jeep electronic/air locking ("Tru-Lok") differential has no clutch pack, a limited slip additive is irrelevant. Their "Trac-Lok" was a friction disc clutch pack that was not electronic. It's too bad we don't have a Jeep diff since their two upgrades are Dana 44's.

Amsoil 75W-140 here. Didn't make a bit of difference in sound or mileage..

I would never use any "enhancer" additives. Choose a good oil like Amsoil or Mobil1 and you won't need any additives. Why screw up their chemistry??

JNR_Design

iTrader: (3)

Actually, I should've been more specific, as this was for a WK Jeep (2005-2010 Grand Cherokee) and with the 5.7 Hemi it came with Quadra Drive II and front and rear electronic limited slip differentials, although they mistakenly referred to the front as a locker. It certainly needed LSD additive in the front especially, and if it wasn't the right kind (the off the shelf additive would not work) and the proper amount, it would start binding and doing all sorts of weird things on turns; especially backing up. Ask me how I know this Most sensitive thing I ever had, lol.

As for the trac-lok (so close sounding to Ford's traction-lok) diff, those were used in the older ZJ's, like my '98 5.9 limited I had...That used a Dana 44 rear, but it was an aluminum housing and more in between a 30 and 44, than a true 44, as far as strength and such.

IIRc, the Vipers and maybe some vette's used a Dana 44 IRS and that would be a nice upgrade for us!

ferny

i used Royal Purple...and im on the original diff. 66k miles