Have a 2013 F350, mason dump, dually, 4x4, 6.7L and have a weird rear end grinding/scraping noise that NO ONE can figure out! All new pads and rotors and E brake components last January via my independent shop. Rear end noise comes when turning at low speeds....like in a figure 8. Couple days ago the E-brake was just adjusted (due to not holding) and they checked if the splash shield were rubbing etc and they are not. Plus they replaced the driveshaft U-joints. Truck only has 19K miles on it.....but it is used to plow snow/salt etc. Braking does not effect, or minimize the grinding/scraping sound. Any ideas??????

 

Has anybody checked the differential?

 

Not in detail......just the tech said he noticed the fluid was "dirty" when he adjusted the Ebrake shoes.....as he needed to take the rotors off etc....and that requires the axle to come out....and some fluid is lost etc.

 

ttt....we go....

 

Check the e-brakes again. The shoe anchor pins will pull through the backing plates Thus releasing the shoes and hardware to float freely around while getting ground up by the rotor. Even with 20K on the clock at least eliminate it as a problem.

 

Wait... You have to pull the axles to change the brake rotors?!

 

Yes, and the rear hubs. The rotors on a dually are bolted to the hubs from the back side.

 

Buy some friction modifier and put it in the rear end, it sounds like the limited slip clutches are grabbing. Very common in the Dana 80.

Denny

 

Ford told me not to add friction modifier to this particular differential????

 

I've put in my 2013 f350 DRW twice to stop it from chattering and it works, I put it in my 2000 f350 DRW 2 times and Ford did it once because of the same problem.

Denny

 

Did you drain the old oil first (or siphon out any).....prior to adding the friction modifier?

 

No I didn't because it's only 4 oz, that's a drop in the bucket when you look at the size of a DRW rear end. Of all the limited slip rear ends I've had in Ford trucks the DRW where the only ones I've had to add it to but they also work the best when it comes to engaging.

Denny

 

Doh...didnt catch the dually thing. Thats why a simple rear brake job approaches 800-1K these days. Crazy.

 

That's why I change my rear pads way before the are do, same thing for the front because the rotors for a DRW 2x4 are very expensive because the rotor is also the whole hub assy.

Denny

 

What is the axle code on your driver side door tag? Look it up and see if it's a LS rear end. If so, add the friction mod and go drive in circles.