Hey guys,
New to the page and wanted to get some input as to what might have caused this to happen. I was picking up a new camper over the weekend and everything was good hauling it home. I was getting back on to the interstate after stopping and had the truck in tow / haul. As I was merging on, the truck stated vibrating (similar to when you hit the sleeper bumps). I knew something was wrong so I slowed and begin getting off the road. That is when my drive shaft twisted in half about 8 inches from the rear U-Joint. The rear end never locked up and I put the truck in 4WD to move so I could hook the camper to a friends truck. All the wheels turned and I did not hear anything abnormal besides the broken drive shaft hitting. Any help / info appreciated. Truck is 2015 F150 Lariat FX4, 3.5 Ecoboost Twin Turbo, 5.5 Bed with 76K miles. Thanks

 

The witness marks on the driveshaft show it was rubbing, or had rubbed, on something. Had you been offroad or high centered? Anything underneath you can see where it was rubbing? Aftermarket exhaust perhaps?

 

That was my first thought also but no. No off-roading or scraping on anything. I let the RV Dealer took my truck to install the hitch and sway bars and less than an hour later this happened. Im sure there was nothing they hit. The only damage to the underside of the truck was a small dent to the muffle. IDK what caused the shinny condition.

 

I agree that the driveshaft has rubbed something at some point. The witness marks behind the break look very fresh. Look under the truck for signs of contact and check rear suspension status to make sure it is properly controlling rear axle.

 

Those scuff marks are for sure the reason it weakened, can you see *anything* it would have rubbed against up under the chassis?

 

Are all the things installed by the RV dealer still present? Any part normally above the driveshaft missing like a cross member? Might ask the RV dealer if they're missing any tools like a breaker bar or a block of wood. Maybe a 2x4 used for leverage?

 

I have no clue what the discoloration came from. The truck is at the shop and they said they saw no other marks / damage besides the dent in the muffler.

 

Well in my business we call that a clue. 1 hour after a hitch install....figure out what they did that caused the d/s to rub something.

 

I crawled under also and say nothing. I called the service manger over the department that installed the hitch and sway bars and he said no lifts or jacks were used. There would be no reason to even touch the under side of the truck in my opinion. There were just installing a hitch to the receiver. It honestly looks like sandpaper was held to it while it was spinning....

 

All they said they did to the truck was put the hitch into the receiver.