Alberto v05

So what fluid goes in the diff?

Exidous

iTrader: (11)

That IS gear oil. The service manual will tell you which weight to run. This assumes you are running the stock rear. If you are running a clutch style LSD you may need different fluid.

ls1 1990 VN

OK, My bad guys!

I have run Redline syn in my T56 & Diff since 04 with never an issue.

The box is Camaro but now fitted with Gears for a Holden VX as it got rebuilt in 04.

My diff is a Salisbury, 28 spline axles, Limited slip. Nothing fancy but has handled my occasional road racing & Drags all the while using synthetic.

Engine uses Valvoline Syn 5w40.

redbird555

iTrader: (14)

the diff takes 75w90 oil and i believe calls for synthetic from the factory but again thats not absolutley necessary. is your car a 98 or 99-up? if its a 98 you have the auburn posi unit and you also need to add the friction modifier to the oil for the posi whereas 99-up got the torsen and that just takes the regular oil with nothing else

Alberto v05

It's a 1999

SSCamaro99_3

iTrader: (1)

Optional Auburn difs call for non-synthetic fluid.

jmd

iTrader: (4)

1999-2002 with stock diff doesn't need friction modifier; it's a gear-bias diff. from Torsen.
SS models (and WS6?) modified from SLP may have an optional Auburn that does require the friction modifier.

bww3588

iTrader: (49)

And non-synthetic oil.

Sales@Tick

iTrader: (3)

We always recommend Dex III in our transmissions.

Stay away from Royal Purple Syncromesh!

If you MUST use a syncromesh use Red Line.

Nemesis350

iTrader: (11)

I think there's a service bulletin that suggests the use of friction modifier (limited slip additive) in torsen equipped diffs that have a "rusty nail" sound of some kind. So a lot of people pour some in just for good measure.