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factory 8.5 30 spline posi?

Posted: Tue Mar 20, 2018 9:18 am
by 81rustabu
Did GM ever make a good factory 30 spline 8.5 posi. i think my factory auburn has finally went.

Re: factory 8.5 30 spline posi?

Posted: Tue Mar 20, 2018 2:08 pm
by prairiehotrodder
are you sure yours is 30 and not 28 ? I don't know the answer to your question because I've only seen 30 spline in 4x4 trucks and they usually have a govloc. If you indeed need a 30 spline posi I would go aftermarket. Eaton, Auburn or a powertrax lockrite in an open carrier are some options.
brian

Re: factory 8.5 30 spline posi?

Posted: Wed Mar 21, 2018 11:58 am
by 81rustabu
I do have a 30 spline posi with aftermarket moser axles. My posi came out of a mid 90s caprice witch do have 30 spline axles. I'm just wondering if they made any better posi units that are factory?

Re: factory 8.5 30 spline posi?

Posted: Wed Mar 21, 2018 2:47 pm
by DOUG213XRJ
I would bet the aftermarket limited slips are stronger then GM.


Doug

Re: factory 8.5 30 spline posi?

Posted: Wed May 15, 2019 9:43 pm
by Doober
I'm planning on a Detroit Truetrac whenever I build the 8.5 I have. No clutches and should hold up fine for the street, if I raced I would probably get the Detroit Locker, to my understanding it's stronger than the Truetrac.

https://www.eaton.com/us/en-us/products ... tials.html" onclick="window.open(this.href);return false;

Re: factory 8.5 30 spline posi?

Posted: Sun May 26, 2019 10:02 am
by LS6 Tommy
Truetracs are kind of weird. Most gear style limited slip diffs are. They sometimes growl or make funny noises, they sometimes make the car feel loose or move around when you lift off the gas in a corner. My new STi has a gear diff in the back and it does the same things as all lthe other gear diffs I've driven.

Tommy

Re: factory 8.5 30 spline posi?

Posted: Mon May 27, 2019 6:35 pm
by malibu795
The true track is definitely "different" in feel from regular clutch/cone posi..
Dodge uses the torsion diff design in there 2500/3500 trucks exclusively.

Never had one make noise... Had a ratchet diff make noise but that's not a torsion doff

Re: factory 8.5 30 spline posi?

Posted: Wed May 29, 2019 7:39 pm
by prairiehotrodder
Auburn has a cheaper one and a better one. Not sure what differences there are besides price.

Re: factory 8.5 30 spline posi?

Posted: Tue Jun 04, 2019 9:03 pm
by LS6 Tommy
prairiehotrodder wrote:Auburn has a cheaper one and a better one. Not sure what differences there are besides price.

X2. Everybody goes for the Eaton, but the Auburn Pro series has much higher torque biasing.

Tommy