F350 With Strange Noise While Towing.

[Dixie_Flyer]

Okay here is the deal. We have a 2012 F350 Ford Diesel with 18,000 miles on it. Driving down the interstate at 65 MPH with nothing in front of you but open highway when suddenly there is a loud thud and a feeling you have just run over something lying in the highway. You feel the vibration come up through the floor board of the truck through the seat so you are sure something has been run over.

You get out and look and there is nothing. No damage no evidence that anything is amiss. Satisfied everything is okay you get back in the truck and start off again. On the trip home we are coming down a mountain and suddenly there it is again. The same noise and feeling that something has hit the truck or you have run over something that was in the road. Once again you stop and look for damage, nothing. There is no check engine light, there is nothing showing up anywhere that anything is wrong and no you haven't been hit by flying objects. We are towing a Montana fifth wheel and if anything was going on back there it would not vibrate through the truck as the Mor/ryde hitch is encased in rubber mounts. What ever it is you can feel it come through the floorboard of the truck.

So can anyone tell me is there something going on with the exhaust that is causing this sensation. Could the engine be backfiring through the exhaust. It doesn't sound like a backfire just a huge thud that vibrates up through the truck as if you have been struck by something.

[Stefonius]

I had the same symptoms once upon a time in a 1973 K5 Chevy Blazer with full-time 4 wheel drive. It turned out that the "thump and shudder" was the front differential self-destructing. When I finally pulled the pumpkin cover off many hundreds of miles later, the ring gear had sheared all the bolts off the carrier and was just spinning freely without driving the front wheels. The mess of twisted and broken metal that came out with the gear oil left me entirely speechless.

Of course, this is NOT what is wrong with your Ford, but it's pretty scary nonetheless, eh?

[ryhed]

I know these trucks have the anti sway control built into the braking system, maybe it is engaging.

[Dixie_Flyer]

These are all good suggestions and worth looking into. I will take it to the Ford dealership where I bought it and let them take a look.

[mchero]

The drive shaft was one of the first things that came to my mind. Might be worth a good inspection.

[westend]

Is there a hanger bearing on the driveshaft? A loose or failing hanger bearing will exhibit the symptoms you describe.

[byronlj]

Do you have an exhaust brake? After I installed mine I would get an occasional thump under deceleration caused by the variable vane turbo.
Dave

[Dixie_Flyer]

harmanrk wrote:
pothole causing traction control/abs to kick in?

Would this make a noise like something hitting the truck?

[harmanrk]

pothole causing traction control/abs to kick in?

[Dixie_Flyer]

Mvander wrote:
Wild guess.......transfer case engaging for no aparent reason. Maybe computer.

Wouldn't that cause the engine RMP's to raise up quickly?

[Mvander]

Wild guess.......transfer case engaging for no aparent reason. Maybe computer.

[MEXICOWANDERER]

Just like a torque converter "issue". Do yourself a favor and have a professional query your ECU for fault codes.

[Dixie_Flyer]

mchero wrote:
WOW - This is going to be a very interesting thread!

Do you feel a loss of power?

Please keep us updated.

There is no loss of power and no change in the RPM's. It is as if you ran over a large chunk of tire left on the road. The sound is not the sound of hitting something metal. It sounds like a huge piece of hard rubber hitting either the camper or truck. This is so strange.:h

[mchero]

WOW - This is going to be a very interesting thread!

Do you feel a loss of power?

Please keep us updated.

[MEXICOWANDERER]

I ran into this in Mexico. A gringo Ford pickup was thumping. After trial and error we finally got it to finally kick into neutral and coast to a stop regardless where the transmission manual valve was selected. Put it in reverse and the truck backed up like normal and all forward gears worked normally again. Not satisfied with that we but the vehicle on jackstands and then further lifted the front or the rear. This made the problem worse with the front end higher. The owner had the truck towed 3oo miles, The Ford Dealer said the ECU had stored no fault codes. He ordered a four thousand dollar transmission from the states. I do not know the outcome.

You need a hotshot Ford automatic transmission specialist's diagnosis if your rig has an automatic transmission. I can offer nothing if it is a manual trans.

[brirene]

Can you relate it to temp control?Although my truck is older, I sometimes get a loud "thud" and quick vibration when the ac compressor kicks in. Been doing it for a while, its intermittent, and doesn't seem to harm anything.