mountainshark76

I want to service rear diff. fluid but I dont see any easy to do it?
I am sure that someone out there has some slick tricks also what brand
posi additive works with mobil one syn. 75w90 thats what I am planning to run
unless you guys say different?

rainman69

Use a 12 point 3/4" socket on the square plug in the diff. AutoZone carries a pump for $10 that is great for sucking out the old fluid. Remove the plug and suck out the old fluid with the pump until there is no more that you can suck.

Then just add new fluid and posi additive with the pump (or get one of the $1 pumps that stick down into the oil container).

I just used GM fluid and GM posi additive. Saw no need for anything else. :smash:

Ryan77

I was going to change my fluid this winter but decided it was be easier to have my mechanic do it, because I'm going to have him install a differential drain plug kit that I saw in an article in the latest issue of Corvette Fever, which will make it a lot easier to change the fluid in the future. I'll get the name of the place that sells the drain plug kit, and post here on the forum.

mountainshark76

Thanks post that when you get it, for now i guess i will be sucking it out :(

Jud Chapin

I would recommend using Mobil 1 synthetic. It's not that much more $ and it is a far superior oil. As they say, synthetic, synthetic, synthetic--engine, trany, differential.
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Larry B.

The only oil related problem I have ever had was with a car that had always been serviced with a major brand of synthetic oil. Now I'm not saying that synthetic oils are bad but it does make me less likely to use or recommend it.


[Modified by silvervetteman, 3:48 PM 12/28/2002]

Dalannex

I got my suction gun from Snap On. It's just a non cartridge (sp.?) type grease gun with a hose on the end instead of a grease nozzle. It works great. (On everything but fords, they have a adjustment nut in the way of the filler hole) I think you would be better off going with the suction gun than the drain plug because with the gun you can get right down to the bottom of the diff., where a plug will always leave a little in the bottom. I feel the gun is a must have tool anyway. I use it all the time. Ever tried to fill a transfer case in a chevy pickup? Another great use for the suction gun. :D

DaddyO

Do I just put the car on rear jack stands and suck out the old fluid?

Ron 75 L48

What I did was jack up the car on one side and sucked all of the differential fluid that I could get out then I jacked up the other side and got what was still sitting in the one side of it. I also used the same gun to put the fluid back in. I cleaned it up real good and it worked great.
:flag
Ron

Eddie 70

Put the rear of the car on ramps. Get under there and suck the old out and refill with some generic fluid. Get out and drive it around the block a few times making sure to take several tight right and left hand turns to work the fluid around good. Come back home and suck the fluid out again. Then refill with the good stuff you want in there.
I did this when my diff was making the chattering noise when turning. This took care of the noise. Never to be heard. BTW, I just put Mobil One in there.