Engine/Transmission (1994 - 1998) Posi traction Problem

[DWJoy]

I have a 96 2500 with 4. 10 posi with 185000. I replaced the fluid with Anzoil at 80000. It is not posi anymore. Only one wheel spins. Do I need to add an additive or do I have a bigger problem? It seems to work fine and I do not hear any noises. With one wheel on ice it is the only one that spins.

 

[Grizzly]

Are you sure you have a Limited Slip Differential? There should be a tag to that effect somewhere. Did you use the correct grade and amount of differential oil?

 

[Bill Lins]

You may have to add some friction modifier (aka "fish oil")- it's available at most parts houses. Of course, with 105k on the Amsoil, it may be time to change again- I do mine every 50k.

 

[kenny61]

The posi units in our trucks suck. What you are describing is "normal"

 

[DieselDoghouse]

DWJoy - in our so-called positracs or Anti-slip-differentials (per the invoice) adding friction modifier ALLOWS slippage. Fossil lube devoid of the additive will cause premature locking and chatter while turning. So that is not the cause. The amsoil you used should be fine. I've heard setting the parking brake slightly will cause anough drag to get the unit actuated. IMHO the best option would be an Eaton e-locker for our dana 70's and 80's - IF they made one!!!!

 

[Rattler]

DDH you are absolutely correct, you can really tell when they don't have enough modifyer in there. I think these things just loosen up with wear also. I can tell mine doesn't work near as well now as it did when new. Randy

 

[JMcCoy]

Yep, I agree. The Amsoil may be too slick for the worn out unit. Also, If you added the friction agent to the amsoil, it might bt too slick. I would try a synthetic lube like Moble 1, that requires the friction additive and don't put any in. If you hear shatter, put in a little at a time. If that doesn't work, try standard fossel based lube. Good luck. Let us know how it goes.

 

[DWJoy]

I was going to try a lube change. It sounds like I should not use Amsoil. If I use fossil lube what weight? The owners manual calls for 90. Or should I use Moble 1 and what weight?

 

[BDaugherty]

You may just need new clutches and discs. I've installed plenty of powerloc and trac loc kits. You may be able to get it pretty cheap from a Dana Spicer dealer such as Atlanta Gear and Axle.

Atlanta Gear & Axle, Inc.



Look for a rebuild kit similar to this one:

Picture is from:QUAD 4 x4

 

[JMcCoy]

Did you ever confirm that you had a limited slip "posi" unit, or and open differential?



If you're going to pay the money to remove the unit, just install a locker of some sort. Traction problems will be a thing of the past.



If you do choose to rebuild your power loc, search online for the old metal clutches. They hold better than the new style clutches.



I have Mobile 1 synthetic 1/2 75-90 and 1/2 90-140. I felt that one was too thin and one was too thick (185,000 miles). Maybe someone hear can advise if the heavier fluid increases or decreased the clutches ability to hold. I don't know. It chattered until I put in approximately 3/4 tube of friction agent.



If I were you, I would go fossil and add a little at a time until it stops chattering. If you have to remove the unit, install a locker. Throw the posi in the garbage where it belongs. Yours can keep mine company HA HA HA!

 

[SRath]

I don't think there are any metal clutches for the dana 80. He may also have a traclok instead of a powerlok, and there is a big difference in performance due to the ramp effect in the powerlok which increases clutch pressure as the wheels spin.

They look very similar and you need to know which you have before buying a rebuild kit.

If you have an open diff after all, you might consider a richmond gear PowerTrax locker that will install into your factory carrier just like a Detroit does on a Chevy Corporate 14 bolt 10. 5 inch diff.

 

[DWJoy]

I know I have a posi. I bought it new. If both wheels are on ice they both spin but if one is on dry pavement only the one on ice will spin. I do not want to replace unless I have to. I will try a lube change first.

 

[JMcCoy]

If that doesn't work, I would try a hand full of sawdust. JUST KIDDING, DON'T DO THAT!!! I had a buddy recommend that to me once. Some buddy huh.



In all seriousness, let us know what lube you try and how it turns out. I believe a lot of people could learn from your results. There is nothing like real world testing.

 

[SRath]

The factory stacks the clutches and plates in less than optimal order. You may just need to restack them for more aggressive lock-up.

My D80 Limited slip was worthless, too. I drained the oil and refilled with synthetic oil and no additive and it made a difference, though it is still just a limited slip and always will be. Meaning if one wheel is on ice or in the air and the other on dry pavement, only the one on ice, or in the air, will spin. There is no substitute for a locker, except a spool, which is not for street use.