just got back from a trip towing a 5500# trailer. On the trip when I would get up to 68-72mph I would get a vibration in the floor and a drumming sound in the vehicle. Been on this trip before and no problem, this is something new.
2004 Ex
6.0L PSD
3.73 gearing

Help??

 

I have a very similar issue with my F250 that I am going to work on tomorrow. It started like yours but mine was above 73 mph. I was on a trip on the highway and I wasn't pulling anything but it was very hilly. I assumed it was a wheel balance issue so I had them checked and rotated when I returned but no change. That was about 3 weeks ago, since then the problem has gotten worse or I may have two problems, because now I have developed a shudder on acceleration and stopping. I cannot find anything obvious that is bad but I suspect the rear driveshaft u-joints. Upon inspection of these there is one bearing cap that the rubber seal/boot is torn and half missing. My theory is that this may have dried up and it causes a shudder/vibration. I'm going to pull the shaft tomorrow and check and replace the u-joints. I'll let you know what I find.

 

have you found the source of your vibration?

 

No I have not. I think I may have a bearing going in the rear end. I say this because I now am hearing a ditinct howl from the rear when I decelerate.

 

I had this vibration before, except it was VERY noticeable. Everyone I spoke to said it was my tires(18" rim with 285/65/18 BFG All Terrains), so I had them balanced. It didn't fix it, so about a month and a half later my transfer case EXPLODED on the highway. I replaced it with a used transfer case and main shaft. I still had a vibration, but nowhere near what it was. Four days ago, I got all the leaf springs redone(about 3" in the front and 3 1/2" in the back). I have a vibration at about 40/km now, when I'm slowing down. I'm thinking u-joints again too. I will hopefully get it checked tomorrow and I will give you guys results. I hope it's not what you guys suggested. Sorry for the long post, but this vibration cost me a lot to fix, so hopefully we can help each other.

 

Do you have the vibration when coasting in neutral?

 

Drive shaft out of balance maybe?Just a thought...

 

Had same problem in a previous vehicle...turned out to be bad universal joint bearings

 

I had the very same vibration problem. In the shop for a week, went through all the boxes and found the torque convertor was shot. Replaced it and it's been trouble free.

 

Yes the vibration happens when coasting too

 

I am having this same vibration. When the vehicle gets up to about 50 mph it starts to sound like you are on a rumble strip. It wases out until you hit about 60 and then gets progressively worse. I know it's not unbalanced wheels and tires as I just purchased new ones. After reading the various threads seems it is most likely a rear end bearing. Does anyone have a part number for this so I can get a new one ordered and or the best place to purchase the part from? Any help is appreciated.

 

I have the same vibration ,sounds like a rumble strip. Mine is rpm specific about 2350-2400 which is 68-70 mph. I can rev the truck and feel the vibration sitting still. If it ever warms up going to change fuel filter, plugs and boots. If you find yours please update as to what you find. John

 

Kind of hoping to revive this thread...

pdx02, you might as well have been riding in my X before you wrote the above. Did you ever find the source of the problem?

 

Same problem at about 55-65 mph.

I figured it was my rear shaft out of balance as I desplined it
(on accident) when doing my rear lift and wasnt sure if it went back together exactly as it came out.

took it to a driveshaft shop and he said it was only out by about 3/4 ounce and he said I wouldnt even feel that. said I probablly need to add a cv joint due to the increase of angle after the lift (4").

so parts are ordered and it will be done thursday.

I would have thought he was BSing me except the Pro Comp directions state that on some excursions a vibration will arise that can be fixed with a CV added to the shaft. So evidently it isnt all of them and of course this would only apply if lifted.

Just thought I would throw that in for those that are lifted.
Good news is that he is rebuilding a bigger better shaft with brand new heavier duty U joints. Bad news $300.

oh and a balance was only $50 so it might be worth just pulling your shaft and taking it down to eliminate that potential issue.

just remember to chock your wheels/e brake as the tranny doesnt hold the truck anymore after the shaft is pulled.

 

I am a bit embarassed to say that I haven't had time to do anything with it yet. Had a death in the family and a bunch of things were pushed back on the priorities list. Going to look into it today. How about you?