Rear Differential question

[robertlb]

All,

 

I've got my 89 up on floor jacks working on the brakes. While I've got it there, I'd like to change the rear differential fluid.

 

Is there anything I need to be aware of before I start?

 

As far as I know, it's never been changed before.

 

Thanks,

Robert

[89eliminator]

i usually leave 1 or 2 bolts on the top of the diff cover loose but still in so when you take the cover off the oil doesn't go everywhere.

[CWLONGSHOT]

i usually leave 1 or 2 bolts on the top of the diff cover loose but still in so when you take the cover off the oil doesn't go everywhere.

 

I agree, also you will need some RTV for a gasket unless you have the paper Jobie. (Even then I prefer the RTV.)

 

Clean both surfaces spic and span clean. Lay down a bead all the way around. Let it set up for a short time. Install but don't torque down right away. Allow the RTV to set up a bit more then tighten down in a criss cross pattern. Fill with hypoid, but don't overfill. If filled properly, you should just be able to touch the fluid if you stick your little finger in the fill hole. Don't for get the add the slip agent if you have a L:S diff.

 

Good luck,

CW

[kawaboy13]

Do you need to install a diff gasket or can you just use red rtv? I am about to tackle my front and rear diff and am wondering what steps I should take and how long I should let things sit before tightening, adding fluid, ect

[ComancheKid45]

Either or, but you can just use RTV without a gasket. just make sure both mating surfaces are very clean before reinstallation. ;)

[MtnClimber]

Or you could get a set of re-usable LubeLocker gaskets. If you do, DO NOT use any RTV!!

[Blue88Comanche]

This might be a stupid question, but what happens if you don't use the friction modifier for the limited slip?

[HOrnbrod]

The clutch packs die an early death from lack of lubrication.

 

As far as diff cover RTV or gaskets, I always use a gasket coated with Permatex 20539. Let it set at least overnight before filling. No leaks ever.

[mvusse]

I used a gasket on the rear diff of my Olds 98 (RIP), but nowadays I use blue or red RTV instead of a gasket. If you're going in there more often a Lube Locker gasket is a great time saving investment.