posi fluid

Transmission to Rear-end

Moderator: Team

Post Reply
dondon
New Member
New Member
Posts: 26
Joined: Wed Sep 09, 2009 6:30 pm

posi fluid

Post by dondon » Thu Jan 11, 2018 10:46 pm

Is that 4 ounce bottle posi additive needed on a 8 3/4 mopar cone type posi or is it only needed for the clutch type posi?

Geoff2
Expert
Expert
Posts: 991
Joined: Mon Nov 09, 2015 4:36 pm
Location: Australia

Re: posi fluid

Post by Geoff2 » Fri Jan 12, 2018 3:15 am

I have a GM axle that uses the cone style posi & it requires LSD additive. Don't see why Mopar would be different...

SupStk
Guru
Guru
Posts: 1491
Joined: Wed Jun 22, 2005 6:25 pm
Location: Box Elder, SD

Re: posi fluid

Post by SupStk » Fri Jan 12, 2018 9:53 am

On a related topic, is the aditive required when using synthetic lube with a clutch type limited slip? Or is the synthetic a bad idea? The differential is a 9" Ford with Trac-loc.
Monty Frerichs
B&M Machine

tresi
Pro
Pro
Posts: 316
Joined: Sun Mar 24, 2013 10:10 pm

Re: posi fluid

Post by tresi » Fri Jan 12, 2018 4:39 pm

SupStk wrote:
Fri Jan 12, 2018 9:53 am
On a related topic, is the aditive required when using synthetic lube with a clutch type limited slip? Or is the synthetic a bad idea? The differential is a 9" Ford with Trac-loc.
I've heard not to use synthetic with a limited slip rear end but that might only be worth what you paid for it.

Geoff2
Expert
Expert
Posts: 991
Joined: Mon Nov 09, 2015 4:36 pm
Location: Australia

Re: posi fluid

Post by Geoff2 » Sat Jan 13, 2018 4:46 am

I always buy rear axle oil that has the LSD additive as part of the oil. That way you know the two are compatible. I see no sense in buying 'straight' oil & adding 'something' to it when all the major companies make oils with the required LSD additive.
One of my diffs was noisy when coasting [ worn gears, no new replacements available ] . Tried two different brand oils to try & reduce the noise, no difference. Then I tried Redline 85/140 syn oil. Noise was almost eliminated, & I ONLY use Redline syn oil now in the axle.

stealth
Guru
Guru
Posts: 1052
Joined: Fri Jun 30, 2006 9:37 am

Re: posi fluid

Post by stealth » Mon Jan 15, 2018 2:04 pm

Geoff2 wrote:
Sat Jan 13, 2018 4:46 am
I always buy rear axle oil that has the LSD additive as part of the oil. That way you know the two are compatible. I see no sense in buying 'straight' oil & adding 'something' to it when all the major companies make oils with the required LSD additive.
One of my diffs was noisy when coasting [ worn gears, no new replacements available ] . Tried two different brand oils to try & reduce the noise, no difference. Then I tried Redline 85/140 syn oil. Noise was almost eliminated, & I ONLY use Redline syn oil now in the axle.
Agree...

Good to hear the redline worked well. Have to give it a try.
The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man.

User avatar
BOOT
Guru
Guru
Posts: 1523
Joined: Fri Apr 09, 2010 6:23 pm
Location: Michigan

Re: posi fluid

Post by BOOT » Tue Jan 23, 2018 4:35 pm

I also prefer the stuff with additive in already that way no matter the rearend you have the correct ratio.
I know as much as I can learn and try to keep an open mind to anything!

If I didn't overthink stuff I wouldn't be on speedtalk!

pdq67
Guru
Guru
Posts: 8142
Joined: Thu Mar 04, 2010 8:05 pm

Re: posi fluid

Post by pdq67 » Sat Feb 17, 2018 8:21 am

I thought that GM's, "Posi-Trac", oil is used with Eaton clutch plate type rear ends?

So cones use it too?

pdq67

Truckedup
Guru
Guru
Posts: 1852
Joined: Mon Jan 21, 2013 2:41 pm

Re: posi fluid

Post by Truckedup » Sat Feb 17, 2018 10:43 am

pdq67 wrote:
Sat Feb 17, 2018 8:21 am
I thought that GM's, "Posi-Trac", oil is used with Eaton clutch plate type rear ends?

So cones use it too?

pdq67
My experience with cone clutch are in the 8.25 Mopar rear used in Jeeps and a GM 8.5 truck rear that appeared to be an after market posi...They are metal on metal if that makes a difference,,,
Motorcycle land speed racing... wearing animal hides and clinging to vibrating oily machines propelled by fire

Post Reply