posi trac ???

[gjacobs]

does anyone know of a way to some what simply make my



limited slip in to a posi trac? I have a 3\4 ton with i think a dana



70

 

[Jim Fulmer]

I don't know but this single trac has to go, what about a locker or something..... anyone!



Jim

 

[Extreme1]

The problem is usually too much friction modifier in the differential.



Try changing the fluid in the rear. Use a good quality synthetic for the refill.



Instead of adding the friction modifier per the DC instructions, drive the truck in a few (8-10) figure 8s in a parking lot. If you get chatter, add the friction modifier 1 ounce at a time and do figure 8s in between each. Stop when the rear acts normal.

 

[Prostock]

To get posi, you would have to put a GM rear end in it.



Posi is a registered trademark of GM.

 

[Floor It]

Posi-trac and Limited slip are two different words for basicly the same thing. Dealer just replaced mine,my limited slip went into a one wheel wonder.

 

[Okie-Go]

I had a limited slip in a Dana 70 with the 98 auto and it was ok. The lsd in the 01 Dana 80 was junk. I could get stuck and one wheel spin the other would look at it. I got me a locker. Now both will spin.

 

[wtrenholm]

Posi-trac, trac loc, power loc are just names of various manufacturers limited slip differential. A typical clutch pac limited slip is not the be all and end all of traction, but they typically do have a nice personality on the street. A guy can destroy a clutch style diffy in an afternoon and it will be useless until it is repaired.



A buddy of mine put loc-rites (sp?) in the front and rear of his Ford plow truck and they are pretty brutal sometimes. Plowing with the hubs locked really sounds scary but it does push good.



Do some research of various styles, maybe read some magazine articles from some wheeler magazines, and look at the pros and cons of each style. It's a lot of money spent to not be happy with.



Wayne

 

[MikeR]

The biggest problem is that the factory or dealer never has the right amount of friction modifier in it. So many guys say it's a piece of junk when in fact they have never checked or changed the diff fluid to the proper mix ratio. Change it, you'll see.

 

[jtisdale]

friction modifier?

My LSD in my '95 worked great, as did the one in my '97. However, this one I got now leaves a lot to be desired. So, all I have to do is go get a gasket, rear end fluid, and some friction modifier from the stealer, drain out my old fluid (10K), and put new in. Then I drive some figure 8's and if I hear chatter, I add friction modifier 1 oz at a time until it goes away? Will it work better after this? It just seems to "loose and lazy" On wet roads it won't even go sideways!

 

[BV]

Hey jtisdale

You don't need a gasket - just some good ole RTV Silicone Sealant. I think most have been using Permatex Ultra Gray

 

[Greg Boardman-RIP]

Limited Slip is the same as a Posi. Can you say two black stripes?

 

[Mark_Kendrick]

Limited Slip is the same as a Posi. Can you say two black stripes?

I like to leave 4 really long ones :-laf

 

[rono]

Hey guys, I don't know what is going on with mine. I got the limited slip on mine but the other day a frind of my sons got stuck (Z-71) and when I was trying to pull him out ALL FOUR of my tires were spinning. I broke the 1/4" chain and he had to call a winch truck to pull him out $100 (ouch). Anyway, I don't know why both front tires were turning.

Ron

 

[Mark_Kendrick]

in 4wd the front axle is 'live' or locked... makes turning a bear.



I used my mule as a cutting horse chasing cows a time or two. hard on a clutch but tons(almost 4 of them) of fun

 

[rono]

I didn't know that! So we can really have 4 wheel drive. Great.

ron

 

[pcorssmit]

No, the front diff is open; there are no traction aiding diffs available for the front. But as long as they both see the same loading conditions, tracion, etc, they will both spin.



Pete

 

[Speedo]

Posi-trac

With all of the information on this site about engines and transmissions there seems to be a lack of information and

understanding about axles and differentials.

To start with an open differential supplies equal torque to

both axles all the time, give or take for frictional losses. While

this sounds good this is where traction problems start. If your

truck has one side on dry pavement and the other side on ice

the side on the dry pavement only gets the same amount as

the tire thats on the ice and sometimes that is not enough to

get things moving.

A limited slip differential, and there are many different kinds,

uses some kind of a friction device, usually clutches, to give a

biased torque to the side with the most traction up to the

capacity of the clutches. Some can be set up differently

depending upon the application so that the clutch pack can

be more aggressive and have a higher capacity, typically for

rear axles, and smoother less aggressive set up with less

capacity for a front axle application. Not all limited slips have

this tuning ability as they were never intended for front axles.

The majority of limited slip designs use clutches and require

some kind of friction modifier be added to the gear lube to

prevent chattering.

Lockers rely on dog clutches to function, in straight ahead

operation they are essentially a spool and only when they

are going around a corner do they unlock the inside axle

to allow different speeds in order to allow turns to be made

without the tires slipping. If an axle is removed or broken no

speed difference can exist between sides so the differential can't unlock. Some of the problems that can happen with a

locker that can cause it to unlock are severly low air pressure

in one tire or different size tires on the same axle. If there

is a difference in tire height but not enough to unlock the differential premature tire wear will occur. The use of a locker

in a front axle normally precludes the use of the vehicle on

paved roads and even off-road only vehicles may have problems

with a locker in the front axle especially with wide wheels.

Spools or welded differentials are normally a race only item

and should only be considered when you know what you are

getting into.

This is a short and somewhat simplified explanation of differentials but I hope it helps in understanding what is

going on underneath our vehicles.

Gus

 

[rono]

Gus, thanks for the information. Both of my front tires were on dirt/gravel so that explains why both tires were turning.

Ron