Positraction pops after being warmed up

[Dan H.]

Recently had my posi looked at and 'repaired' due to excessive play at yokes. Turns out my posi clutch disc were worn, causing play. Shop installed new disc plates, solid steel ones, said they preferred them. The problem: when the car is driven cold, all is smooth, when heated up after a long freeway drive of 90 miles, the rear end popped loudly when I made my first 90 degree turn after getting off freeway. Seemed to quiet down after several turns, but did it again after trip home (90 miles). Seems to be mainly on right side turns, but lesser on left turns. I intend to put another bottle of additive in, has one now. Are there different/better discs out their? Any magic cures? Don't relish pulling the rear our again, will it 'improve' with bunches of figure 8s etc.? Thanks, forgot to mention, it's an Eaton unit, not dana, was replaced long ago.
Dan

[Joe L.]

Re: Positraction pops after being warmed up

Recently had my posi looked at and 'repaired' due to excessive play at yokes. Turns out my posi clutch disc were worn, causing play. Shop installed new disc plates, solid steel ones, said they preferred them. The problem: when the car is driven cold, all is smooth, when heated up after a long freeway drive of 90 miles, the rear end popped loudly when I made my first 90 degree turn after getting off freeway. Seemed to quiet down after several turns, but did it again after trip home (90 miles). Seems to be mainly on right side turns, but lesser on left turns. I intend to put another bottle of additive in, has one now. Are there different/better discs out their? Any magic cures? Don't relish pulling the rear our again, will it 'improve' with bunches of figure 8s etc.? Thanks, forgot to mention, it's an Eaton unit, not dana, was replaced long ago.
Dan

Dan-------


Definitely add another 4 oz. bottle of the GM additive before you try anything else.

[Gary R.]

Re: Positraction pops after being warmed up

Hi Dan,
Posi chatter or hammer has been a common issue with the Eaton posi since the mid 60's. The fact your shop used new solid steels is the best choice, the carbon fibers on the market will smudge and allow slippage but the solid steels are the better ones to use. Now depending on how they were setup could be an issue. Conventional setup with the springs often doesn't get rid of the chatter but as Joe mentions I would make sure to use 2 bottles of the current GM additive and do the figure 8's in an empty parking lot and see if that resolves the issue.

I "tune" every posi I build and still use 2 bottles of additive.

[Russ S.]

Re: Positraction pops after being warmed up

I have had a number of occasions where the additional bottle of additive has fixed the problem also.

[Dan H.]

Re: Positraction pops after being warmed up

Thanks guys, put in 2 bottles of additive, don't know how much of the one bottle the shop got in or spilled, after about 50 plus figure 8s all is smooth now. Even the between gear slight clunk has gone away, I like happy endings !!!!!
Dan

[Gary R.]

Re: Positraction pops after being warmed up

Glad it worked out for you. I never had to do two bottled until the part number and packaging changed a couple of years ago and have ever since. I machine seat the posi clutches and still have to use 2 bottles. Enjoy the car!

[Dan H.]

Re: Positraction pops after being warmed up

Thanks Gary, three times a week I do my figure 8s when the car is fairly cool, so they'll 'break in'. Do the solid discs last longer than the stock composit discs? Next time, I'll ship this puppy to you, and avoid any more grey hair !
Dan

[Gary R.]

Re: Positraction pops after being warmed up

Hey Dan
Well I have gray hair starting now at 57! Maybe too many posi's in my life!!!LOL

You have the best clutches, the solid steels. The fiber coated ones are another attempt at dealing with the posi chattering that has plagued these and other cars the past 50 years. The fiber coated ones are bonded to solid steels and will not typically chatter because the fiber is wearing off as the car is driven. The down side, the coating ends up in the oil, they use less clutches per side, and the springs are huge. I prefer to build and tune my own posi's.

I don't know how your rebuilder assembled the posi but I would wager he built it stock with the springs and plates. Depending on how it was set up will determine life and performance. If you have a 64 vette then it must have a Eaton posi replacement in it because the originals were DANA and parts are long gone now, plus they were pretty weak.

Use the 2 bottles of GM additive with either GM 90 wt or Lucas gear oil. You may find you will have to do another oil change in about 10k miles. Stock up on some additive in case it changes again and also look for some Grecian Formula for the gray hair!

[Edward B.]

Re: Positraction pops after being warmed up

As the Corvette doctor says, "Take two bottles of positraction additive and call me in the morning."