Differential oil

[Tony Radford]

What oil should I get for my Jag diff? Don't you just top it off at the level of the filler plug?

[Jim Harding]

I use 80W90 gear oil and ( if your diff is not open ) 2 bottles of GM Limited Slip Additive p/n 1052358 available from any chevy parts desk. Fill till it just starts to leak from the fill hole..... and it's better to put the additive in first so you don't run out of room for it :D:D

[Tony Radford]

Thanks Jim. I'll pick some up before I reinstall the plate below the differential. It started leaking fluid a couple of months ago after I had it changed for the first time ever. I can't seem to tell where it's coming from. The vent tube was a bit loose and I was able to get another turn on it. There was some accumulation on the drain plug, but it's in pretty tight.

[spd4me]

Jim - What do you mean by not open? Mine is a posi-trac. Both wheels turn same direction when on lift.
Bob

[Tony Radford]

Good point. I think mine is open. I had a spin balance job done recently where they locked one wheel and spun the other with the cars drive train and then did the same with the other side. The mechanic referred to it as an "open" rear end. Does that mean I need different weight oil?

[JeepSnake]

Tony,

You don't need a different weight oil. Plain 80W90 will do fine since you have an open rear. A limited-slip rear has clutches that require a special "friction modifier" be added.

For a good description of:

- Open differentials
- Limited slip differentials
- Lockers

see this earlier thread: http://www.uniquecobra.com/forums/showthread.php?t=7959&highlight=locker&page=2

Hope this helps!