Canadian Tire rear end POSI lube Just want your opinion(s) regarding CT version of GM's posi dif lube. I know that GM sells their own additive (which cost a little more), but as I walked the isle of CT I noticed they cary their own brand of additive that - Any good? or Should I stick with GM's stuff or out of curioustiy, what do you guys recommend? TIA -Andrew I usually shy away from CT, but am wondering, especially if their stuff is made by the same company that makes GM's....

I buy all kinds of stuff from Canadian Tire. For the most part the quality is good. They have good better best stuff just like everyone else you get what you pay for.

Ric

GM offers their lube in synthetic form at 75W-90. Part# is 89021678 and retails for $16.05 (+tax) per 946 mls.

You can get synthetic "high performance" lube at 80W-90 say, in Quaker State from CT, but I generally don't go for QS stuff. I'd sooner take the AC Delco product.

Check out Royal Purple or Lucas, I hear they offer a good product aswell.

The only liqued i would stay away from would anything carrying the NuGold name...i think most of that is just stuff they take out in the garage rebottled...stick with the brand names and you should be fine

Is it a GM-specific lube- or a "generic" posi lube for all manufacturers. If it is for "any" vehicle- I think you probably have the answer on it's overall quality in respect to each/every different manufacturers posi setups- i.e. half-assed.

Hey freestylzz,
the QS stuff, R.P and Lucas - do they come with the posi additive or so I still have to mix in an additive. I've never looked into their stuff closely - always went to the dealer and opened up my wallet there....
-Andrew

Half of the GM dealers don't even know what a 9 bolt is. They tell me to go to Ford.

I've always used the CT Synthetic stuff in the rear of my 9 bolt, with no additive, and it's been fine.

Any lube or additive for a "posi" or limited slip are designed for friction clutch type read ends. The BW or 9 bolt uses metalic cones, no friction clutches. My 92 Jag had a salisbury clutch type limited slip in and it would chatter if I pushed it hard at the track, even with a posi approved lube. I added the GM additive (small bottle) from the dealer to it and the chattering went away. BTW It never chattered on the street.
So for any racheting or cone type diff just a good quality rear end lube is sufficent, Synthetic is the best. Most synthetics are GL-5 , limited slip approved anyway.

god luck and have fun!!
Steve
1988 EX Players IROC
#61
TLMC member

Steve,
After reading your post, I need clarification:
My 92 Jag had a salisbury clutch type limited slip in and it would chatter if I pushed it hard at the track, even with a posi approved lube. I added the GM additive (small bottle) from the dealer to it and the chattering went away. BTW It never chattered on the street.

So even though you used posi addative your rear end would 'lock-up'/chatter and it wasn't until you added GM's addative to the already posi approved lube the chatter went away???
- Strange - I wonder if this was because of the heat being generated from the road course/race usage?
ANyways, just to clarify, most synthetic lubes with GL-5 rating have the posi addative in them? Like Cruz'N Bruz'R mentioned, CT's synthetic is cheaper and if it works fine maybe I should try it...
-Andrew

Yes you are correct, With Gl-5 fluid It only chattered at the track, mostly through the tighter corners. On the street it was OK. My guess was the heat also.

Jaguar specifies a Shell rearend lube,Spriax? if I remmeber correctly. Jag did this because it has the highest amount of additive in it.

Also, any GL-5 fuid, conventional or synthetic will have additives in them. All at different amounts, but they all will have minimum amount to meet the GL-5 spec.

FYI- there is also GL-4 fluid which is for convertional, "open" rearends.
GL-4= no additive, GL-5= Additive.

Rearends that have no clutches do not need the addtive. i.e.= 9 botts, lockers, the rachet styles, torsen etc.

Clutch based rearends do need it. i.e.= salisbury, Eaton, Auburn, some models, 10 bolts.

And YES you cna put GL-5 fluid in a GL-4 type rear end (non clutch based unit).

Hope that helps

Steve

I have been told by a few shops that rebuild 9-bolts (cone type posi's) that the additive is not needed as well.
They recommend using Redline 80W90 (I believe it is synthetic) with no additional additive.
If slight chattering does bother you, only add a small amount at a time until it goes away, never the whole (GM) bottle at once. The additive is a friction modifier and reduces the locking performance of the cones.

I personally have used the GM additive for over 10 years in my original 86 Salsbury cone-type 10 bolt with over 220Kms on it and it still works great..

I plan on using the Redline with no additive this year in my 4.10 9 bolt, we'll see what happens.

Great info guys
I'm going to run a 7.5" 10B rear with 3:42's this season in full open road-rallies - heat will be a problem. I've increased the fluid capacity (a little ) of the rear by installing LMP's alum dif cover, and if necessary may even tap the rear for a diff cooler. Will have to wait and see how everything holds up. This is why the whole issue of rear end fluid came up.
-Andrew
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My car has a spacer between the diff cover and the diff housing, approx 1 inch thick that adds extra fluid capacity to the diff. They added this when it racn Sebring years ago.

steve

Steve,
Any problems with spacing? Does your dif cover interfere with the rear stabilizer bar?
-Andrew

the my rear bar, 9 bolt runs under the diff with about 1 inch of space. No rubbing on the panhard abr or anything.

steve

Btw, for those interested in the AC Delco Limited Slip Differential Lubricant Additive.

Available at any of your local GM Dealerships.

Part# is 992694 and retails for $8.65 (+tax) for a 114 mL bottle.

The additive modifies excess clutch plate friction and facilitates applying and releasing of clutch plates.