Drivetrain clunk at speed

Hey all,

New here. I have a 2013 raptor and have an issue that the dealer is telling me I am crazy because they cannot find it. I taking a road trip and hit an incline at 75 mph the truck down shifted and there was a loud clunk from the rear end. Felt like something fell out of the bottom of the truck. Since then when I start the truck there is a grinding noise from the rear when the truck. Sound metal on metal. It seems to be only when cold start ups. Any thoughts on what this may be?

Could be any number of things with that description unfortunately. Best bet is to let dealership keep the vehicle so they can produce the cold start ups. Reach out to the Ford Rep on this site and see if she can get the ball rolling. Are you still under warranty?

Have you checked for leaks around the driveshaft & axle? Could be something loose in the pumpkin. Does the rear locker work properly?

Is the noise there only during start up, or during initial driving?

Have you figured this out yet?

I started experiencing something similar the last couple days. It's a grinding noise that sounds like the driveshaft is rubbing against the muffler or something. It only happens when the truck is cold, in gear, and at low speeds. It only lasts a couple minutes and then goes away.

For the record, I did have my muffler break the other day. The factory weld on the inlet pipe & muffler came completely separated. During that time it did rub up against the drive shaft and cause a few scraped rings in the driveshaft. I had the muffler re-welded and I took my truck by a driveline specialist this morning to look at the driveshaft. Two techs crawled under and looked at it and determined it's just cosmetic damage and told me I wouldn't need a new driveshaft.

I know the muffler isn't rubbing on the driveshaft now. And I'm a little paranoid as I've already cratered a transfer case because of a dinged & off balance driveshaft. That was a completely different noise though.

I've crawled under my truck and no fluids are leaking anywhere.

Update: I believe it was in fact my muffler banging against the driveshaft or something else. I crawled under there again and was able to get the muffler to move around and with enough force could push it to touch the drive shaft. Perhaps when it was cold it was pulling the muffler hard enough to rub against something.

I fiddled around with and was able to move it into a position that felt like it kind of locked into place and wouldn't move around after that. No noise since then. Bottom line, I need to move this muffler back to it's original location (it's lightening style right now).