roy69

OK - while the car is up on jack stands and I'm scratching my head about the left rear wheel (separate thread), and everything is good and warm, it seemed like a good time to change the oil in the rear end - which i've been putting off for some time.

I had 2 bottles of the GM lube and 1 bottle of the limited slip additive. From the threads I've read, and the manual, I expected to have the rear end full before I finished putting in the second bottle. It isnt. Now, I'll be honest, there was some that made it to the garage floor instead of the rear end, but not that much. Is this common? (not the deal with the floor , but the rear end not topping off)

The label on the GM lube says its 80w90 GL-4. Can I top it off with another brand of this, or do I need to get the GM stuff? I ask because I dont have a local source for that.

trw

I bought 3 bottles and have 3/4 of the 3rd bottle left.

I would buy another.

ssenay72

Me too, just did mine today 2 & 1/4 bottles and 1 posi add.

kingkohlmn

Same here, just be sure you add the little bottle of the GM stuff. That did the trick no more dif noise, but of course, I now hear all the other noises.


Thanks Bill

roy69

Thanks all

la1234

To my understanding, U'll need 2 additives:
http://forums.corvetteforum.com/c3-t...rear-diff.html

tomgallucci57

what size socket did you use to take the filler nut out?

pws69

Myth - don't know how this got started! One is plenty - 2 is wasting your money.

PRNDL

Same grade/weight oil would be totally compatible. I bought the GM stuff but personally would not hesitate to blend in a small amount of another brand.

My owners manual has the capacities in the back, including the differential. Got one of those? (owners manual)

I have a vague memory (most of my memories are vague) of GM making 2 different sizes of the limited slip differential additive, which can make it a little confusing when you are trying to figure out how much additive to add.

G-Sting

A 3/4" 12-point socket fits perfectly over the square filler plug to remove or to tighten (20 ft-lb).

Also, one can use a 50 cent snorkel funnel from Walmart to attach to the oil bottles to fill it up. Like this:


Enjoy!

roy69

I had a 'date' with to take my granddaughter on a cruise today - which I wasnt going to break -- so I topped it off with some Royal Purple. No problems. I will probably change it again in a few weeks. I know there are some that may say it is unnecessary - but what came out of there was pretty nasty. Next time I'll have the third bottle of the GM stuff and not have to worry about it.

Thanks all

(Oh yes - a 3/4" socket works fine)