I had these replaced under warranty, but they are shuttering again. Anyone know what it will cost to have this repaired? No more warranty!

 

I don't know how much it would cost to repair your OEM LS unit, but since it will be on your dime, you might consider an aftermarket unit. You can get a Truetrac unit for the 9.75 diff for less than 5 bills, and they a simple bolt-in, no special tools needed.

 

your looking at 125 for the clutch paks and then the labor to install them.

 

A cheaper solution to try is to add more friction modifier. Drain the diff, add about 6-8oz of modifier (Ford calls for 4), refill the diff with 75W140 synthetic gear oil. Ford used to spec 75W90 but has since changed that to the heavier oil.

 

I asked the service manager at the local stealership about what I could do with my chattering clutch packs. He said I could try the cheap route of adding friction modifier and driving it around awhile or the expensive route of a out of warranty clutch pack rebuild.

I'm a cheap SOB and went that route. That worked for me although YMMV.