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.

[BigJon05]

I have the same problem on my 03 6.0 F350. We tow a big FW toyhauler and sometimes I hear a thud thud thud noise coming from the drivers side engine compartment. Mostly on climbs. If I let off of the gas and them reapply it will go away. I have been wondering about it for some time now. Funny that I found someone else with the same issue on the forum I like the most!

[Dixie_Flyer]

brirene wrote:
Hey Dixie Flyer, any diagnosis from the dealer on the issue?

Okay I had to go back and find the work order from the service shop. The bearing on the drive shaft had nothing to do with the noise but while looking they found that the bearing did have too much slack so it was replaced.

The noise was coming from the sway control on the truck engaging the brakes causing the anti-lock sensor to give a loud thud that you could feel coming up from underneath the truck. A sensor was replaced for that.

[Dixie_Flyer]

brirene wrote:
Hey Dixie Flyer, any diagnosis from the dealer on the issue?

It was a drive shaft issue. Back pressure on the drive shaft when coming off grades with the transmission in tow mode. At least that is what was explained to me. Does that make sense to you?

Oh I forgot, it also had something to do with the sway control on the truck engaging the brakes or some fool thing.

[brirene]

Hey Dixie Flyer, any diagnosis from the dealer on the issue?

[j-d]

I've had a shock absorber (actually a strut on an FWD car) stick in the down (compressed) position. Could look at the car and notice that the front end looked low. Try to bounce the car and it wouldn't want to move, till it let go. It'd jump back to normal height with a BANG because it was holding back the spring pressure.

[Harvard]

Check the rear mount of the transmission to make sure it is tied to the cross member and not free to move laterally.

[Dixie_Flyer]

CR CRUISER wrote:
Is your truck 4 wheel drive? Any chance you were driving with the 4WD engaged? That will cause the driveline to load up between the front and rear until something has to slip, usually a tire momentarily. This will sound and feel like what you experienced.

I don't think so. The computer lets you know when you are in four wheel drive.

[CR_CRUISER]

Is your truck 4 wheel drive? Any chance you were driving with the 4WD engaged? That will cause the driveline to load up between the front and rear until something has to slip, usually a tire momentarily. This will sound and feel like what you experienced.

[Charlie_D_]

Jack up the rear end, start engine, put in drive and see if tires are out of round.

[Dixie_Flyer]

Mvander wrote:

Dixie Flyer wrote:

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?

Only if engaging low range.

Okay?????? Never thought of that.....

[Mvander]

Dixie Flyer wrote:

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?

Only if engaging low range.

[mena661]

Thanks, keep us up to date.

[Dixie_Flyer]

mchero wrote:
OK, I'm waiting to find out what the noise is\was! Any update from the OP?

It is going to the Ford dealership next week to look at the drive train mainly the driveshaft and bearings. Also they are going to look for codes in the computer.

[mchero]

OK, I'm waiting to find out what the noise is\was! Any update from the OP?