Posi additive for Mid Year

[Terry D.]

Re: Positraction additive

GM's additive # 88900330 is $8.97 at Summit Racing

[Gary R.]

Re: Positraction additive

I have used a lot of the GM additive over the years, all with tuned posi's and never had a problem until I noticed the part# and packaging changed a few years ago. I never had a tune posi chatter, yet this one did on a road course. Before tearing it down the owner drained the diff again, already had 5k miles on it, and installed new lucas 85-140 with 2 bottles of the new GM stuff- that solved the problem. I can't say for sure the chemistry changed at that point but something was different, I use 2 bottles now and never had another issue. Jack Panzica is a good testament to that in the recent past.
Now with a stock spring load posi I would also use 2 bottles. With the new loaded Eaton and fiber clutches it doesn't matter as much because they are going rub themselves down to the bare metal anyway and start to chatter with those huge springs used.

[Joe L.]

Re: Positraction additive

I have used a lot of the GM additive over the years, all with tuned posi's and never had a problem until I noticed the part# and packaging changed a few years ago. I never had a tune posi chatter, yet this one did on a road course. Before tearing it down the owner drained the diff again, already had 5k miles on it, and installed new lucas 85-140 with 2 bottles of the new GM stuff- that solved the problem. I can't say for sure the chemistry changed at that point but something was different, I use 2 bottles now and never had another issue. Jack Panzica is a good testament to that in the recent past.
Now with a stock spring load posi I would also use 2 bottles. With the new loaded Eaton and fiber clutches it doesn't matter as much because they are going rub themselves down to the bare metal anyway and start to chatter with those huge springs used.

Gary-------


I've always used 2 bottles.

By the way, I was in my local AC Delco auto parts store today and they had the additive on the shelf. It was packaged in an AC Delco-labeled bottle and it had both the AC Delco "short" part number as well as the GM "long" part number.

[Keith B.]

Re: Positraction additive

I guess no one got it when I offered my little pun. Guess I'm dating myself, but it used to be said that the additive came from sperm whales and it was a common pun to transpose the two words leaving some commandos to believe the transposed verbiage to actually be the source. Am I the only one who remembers this? I used to wonder how they got it.

Stu Fox

my relative who worked at a local Chevy dealer as a mechanic in the 70's to this day calls it whale juice. I never understood why he called it that. Now it's making sense.

[Stuart F.]

Re: Positraction additive

As a retired GM employee, I Get at least a 10% discount at most any auto dealer including most non-franchised auto parts store just by showing my GM retired ID card. It's not much, but every little bit helps.

Stu Fox

[Scott S.]

Re: Posi additive for Mid Year

The GM stuff is junk. Go to your closest Ford Dealership and get 2 bottles of Friction Modifier. It's in a white bottle with a red label. I have saved at least 4 members before their PV thinking about having the rear Differential rebuilt. The Ford stuff solves the chatter problems!

[Terry D.]

Re: Posi additive for Mid Year

Scott
So does the GM product and if it doesn't you have more wrong with your rear end then you think!

Terry

[Duke W.]

Re: Posi additive for Mid Year

Regardless of where you buy it... GM, Ford, Mercedes, NAPA..., it's the same chemical blend because all use the same technology in their LSDs.

Duke