My '84 4X4 truck is supposed to have positraction. It turns both rear wheels but is the front axle supposed to do the same?

But, when using it in sand or snow, it does not appear to work well or at all.

How can I test it properly and then what is involved to service the insides?

 

Fords posi is called Limited slip, its a clutch pack that will alow each axle to break loose from each other in turns on pavement. It helps reduce excessive tire skuffing in turns.

With both rear wheels off of ground and tranny in nuetral, rotate one rear tire, the opposite side will rotate the same direction. This is all fine and dandy, it does not tell you how tight the clutch pack is gripping! I am sure there is an engineers answer for this, me being a retired grunt, I find loose sand in a wash and punch it. If the rear end hops, both of my rear wheels are pulling their share.

I have never seen LS installed in front ends, only in the back. But my exposure to what is out there is very limited. My 88 Bronco II has LS in rear and not in front, I can get into trouble if I get real light on diagonal tires. They spin just fine but no weight means no traction. Hope this helps.

 

The axle codes on the door sticker will tell if you have LS or not.
Never heard of LS stock on front axles.

Limited Slip is just what it says.... limited. A lot of folks have unrealistic expectations. It's not spool or locker!
If both rear wheels have the same amount of traction, (or equal lack of traction), then LS does nothing.
LS only works when there is a difference in traction one side to the other.

Find a spot in a road where you can straddle dry pavement on one side and mud/ snow/ sand on the other side. Do not engage 4x4!

You need to get the wheel in the sand/snow spinning a bit. Not all out...
If LS is working then the truck will move forward. If not working the wheel on solid ground will not move and the wheel on the slippery side will spin like mad.
Repeat for the other side.

Here is a short video showing both LS and no LS...

You can get clutch rebuild kits for the LS. Also you must have a special additive in the diff.

I had an ARB air locker put in my axle... costs a bit of $...

 

If you raise one rear wheel, with the truck out of gear, and try to turn the raised wheel by hand, it should take considerable force to do so. If you have a beam, or dial type torque wrench, put it on one stud of the raised wheel, anything less than 50ftlb and the clutches are probably worn. Excessive amounts of the limited slip additive can cause slipping, if you buy Castrol hypoy C gear oil, it already has the additive mixed in. The purpose of the additive is to allow , or CAUSE clutch slip, so you don t hear clutch chatter, or get sideways every time it rains. I avoid the stuff, for that reason, and my diffs have been fine for years.

 

I will use the torque wrench test to see if the clutches are working well.

 

Guess I will have to replace the differential clutch packs as it slips too easily. The rebuild kits say they have instructions?

Has anyone done this job and have any hints as what "not to do"?

 

Took off the rear end cover plate and there was lots of clutch material in the oil. Ordered a whole Traction Lok rebuild kit and it will arrive on Tuesday. Does not sound like a very big job to put in the new clutches.

Will measure the torque to turn the wheel when all is installed and report.

 

Put in a Ford Racing clutch kit and now it is working properly. Took (4) four hours to complete the job.

The cost was $69.95 for the kit, a $6.00 Felpro gasket and 2 2/3 qts of lube. Hardest part was getting the new shims to fit properly inside the rear end.

When done, I re- measured the torque required to turn the drivers side wheel
with the other wheel on the ground - my torque wrench pegged at 100# and the wheel did not turn.

Before the kit, it took 25# of torque to turn the wheel.