I remember yous guys talkin about changin your rear dif oil and having questions about Royal Purple and GM posi additive, except I can't remember if I have to add the GM stuff if I use the Royal purple or not.This will be my first time changin the stuff, any tips for a newbie?I assume there is a gasket for the dif cover, where do I get that?I can get the royal purple at CT right? Are there different grades or is it all the same?Do the bolts need to be cleaned up before re assembly and do they need some kinda gunk on them or do I just slap it back together???

 

I forgot to add, my posi unit is acting like a peg leg so I'm hoping the oil change will help get it working again. More than likely the posi unit is trashed. Is there any way to tell by just lookin at it once the cover is off?The rear doesn't make any whinning or clunking noises and seems to perform allright other than leaving one strip of rubber on the ground.

 

If you go with Royal Purple than you won't need the additive. Royal Purple already has an LSD additive in it so it would be overkill. I've got Royal Purple in my diff right now. I've driven about 2 months at the end of the summer with it in and no problems at all as far as I know.

You can buy the Royal Purple at pretty much any speed shop. Out your way it's probably Karbelt. Expect about $15 per bottle and you will need 2 bottles.

The gasket is best bought at GM, I think it was about $15. And you'll need a small tube of RTV as well.

Once you drain your fluid, clean the diff out with some brake cleaner and let it sit for a day if possible to let it all evaporate (but this is not required, just my preference).

Make sure all the matting surfaces are completely clean and free of old gasket material and grease so that the new gasket and RTV will set probably and not leak on you. It's good practise too to clean up the bolts and stuff. You can use whatever is left of the brake cleaner for that.

I hope that helps.

 

amsoil is another good choice for the rear end.

 

Very true...I think it's a little harder to find a supplier. But it would be another good choice if you can find it.

 

Karbelt carries amsoil usually.

Just to give you an idea of how fine amsoil is of an oil, if I run amsoil, I will get smoke on startup in the morning due to my old valve seals...

I won't when running mobil1... that much finer of a synthetic oil.

 

maybe its thicker

Daz

 

when i had my tranny built, all ive used is Amsoil. full synthetic. the rear i put royal blue. and run 10w30 mobil1. never had a problem, but its expensive come spring time when i change everything hahhaha. its sittin outside my door as we speak. over 150$ in oil hehehhehe and filters.

 

Well i cheaped out!! I don't really care if my rear pops so I am trying 2 bottles of GM additive and MOTOMASTER FULLY SYNTHETIC 75W90 FULLY SYNTHETIC OIL... hahahahaha that crap was like Orange when I put it in... we'll see how it works this year..

boy am I going to here about this one!! ahahahaha let the flaming begin..