Hey guys I was just wondering what yo uwould do in this case. The posi kicks in when in the snow or dirt but it wont work on pavement at all anymore. The truck as 72k on it and im about ot change the rear fluid, will the friction modifier stuff make that much of a difference? or help at all? also is it bad to drive it if the limited slip stops working? Thanks for any help!

 

Changing the fluid is good for the differential in general, but it will not help the limited slip. If ithe clutch's are worn you need new ones. It won't hurt to drive it with worn clutch's; provided all other components in the rear are ok.

 

everything he says is right on the money..limited slips that ford uses have clutch packs in them that are pressed together with a z lookin spring...over time just like any friction material..they wear out..nothin to freak out about..just like doin breaks or clutches...normal wear and tear..i have a LS as well..and its not at its top dog performance as it used to be..changing the oil and adding the friction modifier wont hurt..but to ultimately fix the problem gettin new clutch packs would be the way to go...

 

You may want to try changing the fluid and NOT putting in the friction modifier and see if that allows the clutches to grip a little more.
The purpose of the modifier is to allow the clutches to release smoothly when turning. It sounds like it may be worth a try. Although if your model specifies synthetic, it costs about $15/qt for the oil unless you buy the Walmart brand which is about $8/qt.

I'm not sure what the clutch pack costs, but if you find a dealer who will sell at a discount, it may not be so bad. A complete Traction Lock unit isn't much more than $200 new (wholesale).

There are dealers who will sell wholesale by mail order.

 

 

Yes the clutch packs will wear out after about 125 to 150 thousand miles. If they did not wear out then why would Ford sell rebuild kits with just the clutches and modifier? Changing the clutch packs is and easy, garage fix. Pull the cover, pull the cross shaft, pull the C-clips, the side gears and spider gears will fall out when you rotate the assembly. Put the new clutch disks and spacers in the same way they came out and repeat the steps to reassemble. Couple of hours tops. You can buy the gear lube "with the modifier in it" but I would still recomend using the regular oil and adding the modifier yourself.

Hope this helps

Steck

 

 

F

 

 

Actually most people that change the fluid in there differential will take the cover off to drain the fluid. That way you can clean the bottom of the differential out were most of the sediment will settle.

 

 

U

 

 

C