Author Topic: 12 Bolt Posi question  (Read 2897 times)

cwyllie

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12 Bolt Posi question
« on: March 25, 2022, 12:12:21 AM »
 So I noticed as I was pulling my car into the garage, that my diff seemed to be binding. It was almost like a catch or pop if you will. The front wheels were turned and slightly uphill. I drained and replaced lube along with additive, did 20-30 figure 8's in reverse, drove her home and had the same issue.
Is this normal for a Posi? Thank you for any input.







GMAD_Van Nuys

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Re: 12 Bolt Posi question
« Reply #1 on: March 25, 2022, 12:42:06 AM »
Unless your car has a Detroit Locker, you shouldn't experience any binding with a Posi.

69Z28-RS

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Re: 12 Bolt Posi question
« Reply #2 on: March 25, 2022, 02:55:14 AM »
you may need to renew or replace your positract lube additive.
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x66 714

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Re: 12 Bolt Posi question
« Reply #3 on: March 25, 2022, 11:56:57 AM »
So I noticed as I was pulling my car into the garage, that my diff seemed to be binding. It was almost like a catch or pop if you will. The front wheels were turned and slightly uphill. I drained and replaced lube along with additive, did 20-30 figure 8's in reverse, drove her home and had the same issue.
Is this normal for a Posi? Thank you for any input.

You don't say exactly what fluids & posi additive you used. Can you be specific on brands, weight, & type?....Joe







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firstgenaddict

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Re: 12 Bolt Posi question
« Reply #4 on: March 28, 2022, 08:13:43 PM »
I use the GM additive for the posi in whatever amount they call for...
There is also a name brand or two with the additive already in it.
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rszmjt

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Re: 12 Bolt Posi question
« Reply #5 on: March 29, 2022, 12:18:04 AM »
GM/AC Delco additive #992694

cwyllie

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Re: 12 Bolt Posi question
« Reply #6 on: March 29, 2022, 01:04:42 AM »
I used Valvoline 80-90 High performance gear lube and one bottle GM limited slip additive 88900330.

x66 714

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Re: 12 Bolt Posi question
« Reply #7 on: March 29, 2022, 01:20:34 AM »
Maybe somebody set the clutch packs a little tight. Just a thought...Joe
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Kelley W King

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Re: 12 Bolt Posi question
« Reply #8 on: March 29, 2022, 11:42:55 AM »
Clutches could be worn. I had a 10 bolt some years ago that I tried everything else on and ended up replacing the clutches to cure the binding.
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Stingr69

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Re: 12 Bolt Posi question
« Reply #9 on: March 29, 2022, 03:25:45 PM »
If it were mine, I would start with fresh GL4 gear oil and 1 bottle of the GM limited slip additive then do the figure 8's.  If it still snapped on turns, I would add another bottle and redo the figure 8's.  If it still snaps after the second bottle, I would do an overhaul on the differential.  Probably send it to Gary Ramadei if I could not find a trustworthy local shop to service it.

cwyllie

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Re: 12 Bolt Posi question
« Reply #10 on: March 30, 2022, 01:21:50 AM »
Thank you all for the input. Much appreciated!