korvette4u

at the dealer today.. they said just changing rear axle in my stock 89 vet , can be done with synethic 75-90w, with out axle friction modifiers for limited slip.. is this true??

what oils can be recommended here by the forums members?

thaks

WW7

Most of the Synthetic rear end oils do have the limited slip fluid already in them..WW

TimV SR

Any problems using the synthetic and the additive?

Kubs

I use Amoil Severe Gear synthetic oil and it already had the additive in it.

korvette4u

very good question????


what weight and service rating is best? and how much oil needed to change?


from amsoil
Limited Slip Differential, Rear......GL-5*
All TEMPS......80W-90 [5] [4]
SAE 80W-90 Synthetic Gear Lube (AGLQT)
SEVERE GEAR 75W-90 Synthetic EP Lubricant (SVGQT)
75W-90 Synthetic Long Life Gear Lube (FGRQT)
SEVERE GEAR 75W-110 Synthetic EP Lubricant (SVTQT)
Limited Slip Differential, Rear......GL-5*
All TEMPS......80W-90 [5]
SAE 80W-90 Synthetic Gear Lube (AGLQT)
SEVERE GEAR 75W-90 Synthetic EP Lubricant (SVGQT)
75W-90 Synthetic Long Life Gear Lube (FGRQT)
SEVERE GEAR 75W-110 Synthetic EP Lubricant (SVTQT)


[4] 1984-90, In Canada use 80W only.
[5] Limited slip identification: tag under cover-attaching
bolt. Models with limited slip use 4 oz & 4.7 oz on 2007-08
XLR, 2006-08 Corvette Except Z06, 2006-08 Z06 6.8 oz
GM part no. 1052358 additive or equivalent when fluid is
changed.

change requies 3.2 pints ..??? what is a pints ....your guess less 4 oz..

korvette4u

oppps i learning how to TT...

engle1147

When my old high mileage ring and pinion gears came out I went deeper with tooth count on the new gears but I went back with what oil and additive that came in the car from the factory....no problems to date. If I remember the D36 took a quart + one bottle of additive.

C66 Racing

I'd recommend this one:AMSOIL Severe Gear Extreme Pressure Synthetic 75w90 (Product Code SVGQT)
and for the DIYer:
AMSOIL Hand Pump (Product Code G2039)

That fluid comes with friction modifier already in it and is the same fluid I use in my 02 Z06 which is now exclusively a track day car, and used in my 06 CTS-V which was my daily driver for about three years.

twin540

I used amsoil with additive. That might be the reason I get a slight moan on slow turns. I'll try the oil by its self.

c4cruiser

Get two quarts of 80W-90 gear oil from any parts store, add a bottle or two of the GM Positraction additive and that is all you need for street use.

GM did not specify a synthetic gear oil in any C4 so my take is that the dealer is trying to upsell you on something you really don't need. I have used the oil combination above on my 87 for 7 years now doing autocross and track days, The posi still works fine, no whine from the diff, and no leaks.

Ray Quayle

Hey Subdriver, Ever have to get the serial number from a water slug?

korvette4u

changed it today: 3.2pints-75-90w quaker syn and 4oz limited slip additive .. done and it took about 12 beers amongest the help

being an amsoil dealer , it does quote to add the limit slip compound in the tech section..just as i quoted above... even to c-5, c-6 some application!!!

PLRX

Use Royal Purple and you don't have to buy additive.

korvette4u

Royal Purple Ltd. was black and blue after BP Lubricants USA took it to task over advertising claims for its synthetic motor oil, finding a receptive audience in the advertising industry’s self-regulatory forum. Review the Full Article

THE REAL PROOF

REMEMBER THE old saying "you were told ,right?" so ya do it! no reseach, just repeat this ''if there is a cliff, jump off?" na i dont think so

C66 Racing

I think that is a little misleading. All that section states is what GM recommends, not how to accomplish it. GM does recommend limited slip additive. But, that comes in the AMSOIL gear lubes, vice needing to be added separately. The vast majority of C4 and C5 diffs do not need more friction modifier than comes in the Severe Gear to prevent diff chatter. Note that is not the case for the C6 if anyone with a C6 is lurking in this forum.

For Ray - been looking for those serials for a long time, can never seem to find them!

korvette4u

WHERE DOES IT SAY "NOT to ADD THE ADDITIVE???

JEEZ just wanted to change rear end oil . the old c-4:S required the additive. i havent run across an oil where the API rating includes slip modifiers and "recommends no additive".. IF IN doubt about "YOUR " oil change do some research..

changed mine using castrol syn 75-90W and an additive.. NOT USING AMSOIL!!

thank you for all your suggestions