diff. oil ?

[denn454]

I got a posi today, went around gettin all the seals, C locks, and gaskets and everythign but i didn't get any oil. the GM posi lube stuff is a lot bit pricy from what i have heard so I'm looking for somethign else, possible something better. What do you guys use? I've hard the synthetics don't need a posi additive, do they? whats the best stuff to get? its a stock GM posi...

[d0n_3d]

i run mobil 1 synthetic gear oil...you can buy it from autzone for like 6.99 a quart...

haven't had problems with it yet since i put it in 2 years ago...i am putting in new moser axles so i have to refill my diff. putting the same stuff in...i believe it has the posi additive already in it

[Jeff Rand]

I know this will open a can of worms but Tom at Tom's Differential does not recomend synthetic oil. He sells and installs either Torco or Lucas with the non slip additive (he uses 2 bottles of additive with new posi's). Tom said that all his tests showed more wear with the synthetic. I have been following his advice for many years and have not had any issues.
Good Luck,
Jeff

[denn454]

what kind of posi additive? I do like the idea of cheap normal stuff more than synthetic, if it works. I don't know about ammount of wear that synthetic protects from, but i do know that its a better type of oil as far as performance goes. In my old car (75' Vega) I used the cheap stuff for the longest time then tried some synthetic and it was a noticeable difference, it was still slow but it did make a differennce. So i think the same would be true with a rear end.

[GNVAIR]

My preference has been to stay away from synthetics for rear axles as someone else has already posted.
It really does more harm than good as it doesnt have quite the "cushioning" effect that regular gear oil has. As some of the guys who work for Ford dealerships about rear axle bearing failures on the light duty trucks and Mustangs. Much of it has been attributed to the synthetic fluid Ford specified.
My personal preference is Kendall gear oil with 2 bottles of the Ford friction modifier (the blue-green colored stuff).

[2quiktocare]

Ok, when it comes to posi fluid and additive, let me tell you some of my many experiences from being at GM and elsewhere.
The only thing that I have ever seen truely perform the way it was engineered to, is diff fluid with the not really that expensive additive. Jeff is right, you need to add two bottles. Synthetic will get you by, but when you are talking long range life, you can't beat dinosaur goo with posi additive. Use the GM stuff, it is the best period. I know that will upset someones sensibilities about their own idea's, but I would rely on the people that have their name on the line here. I have made too much money from people not running the right stuff on the backside there. Just keep in mind that old commercial, " you can pay me now, or you can pay me later"

[MeanBuicks]

Originally posted by 2quiktocare
Synthetic will get you by, but when you are talking long range life, you can't beat dinosaur goo with posi additive. Use the GM stuff, it is the best period.

I concur. I change the fluid in my diff. every 100,000 miles so I've done so twice thus far with standard gear oil and GM additive. 220,000 miles on the factory G80 now and it still works like a champ. That's still original seals, bearings...everything.

[HOTTOGO]

I third the motion of standard petrolium based w/GM additive, but check the shevles many fluids such as Valvoline come with additive already in it?!

[denn454]

Originally posted by HOTTOGO
I third the motion of standard petrolium based w/GM additive, but check the shevles many fluids such as Valvoline come with additive already in it?!

I was thinking of somethign with the additive in it to save some money. from what i have heard the GM stuff is really expensive. is the autozone stuff good enough or should i go for the gm stuff, and how expensive is it?

[HOTTOGO]

It's just a 4oz bottle

GM PART # 1052358
GM LIST: $7.21
OUR PRICE: $4.11

www.gmpartsdirect.com

[2quiktocare]

Sounds like a cheap price for the right part ot me Mark,,,,,,,,
Make sure you use two if them also

[turbo nasty]

how much is the shipping though??????????

That usually is the kicker on the gmpartsdirect site.

What I prefer and is always cheaper is partszoneonline.com it was considerably cheaper than gmpartsdirect on TV cable, o2 sensors, top engine clean, etc.
Give it a whirl and they are a gm dealer.