i was pulling my trailor last night and as i was going up a small hill my truck started to vibrate pretty good, as soon i leveled out it went away. anyone else have this problem or know of anyone who has? it almost seems like a bad universal joint but with 13,000 miles on the truck i cant see that being the problem.

 

My 08 XL has done something very similar, and it was when I was pulling just a 400-500 pound, empty trailer. I thought it was odd, but it only happened once. It felt like a long, slow vibration as I was climbing the hill. I contributed it to being that I was lugging it in 5th gear rather than downshifting to 4th. What are the details of your F-150?

 

bone stock xlt 4x4 5.4l i was pulling a 6x12 open trailor with 2 sport qauds which is no where near what the truck is rated to pull maybe 2000 lbs tops, it did this to me before but i figured it may have been a fluke, but i guess not. hopefully someone can help me out with some info because i just ordered bigger tires and a level kit and i wanna get it to the dealer before i install everything because you know thats where they will point the blame.

 

Happened to me once while pulling a 12ft utility trailer with maybe 800 pounds on it. Thought I had a tire going down or coming loose it was shaking so bad. Turned the overdrive off after stopping to check the tires and it didn't do it anymore. I was going up a pretty long uphill strech of highway when it happened.

 

my overdrive wasnt on when this happend.

 

sounds like the trailer is pushing the rear of the truck down far enough to throw the pinion angle out of whack and cause a driveline vibration. What you guys are describing sounds exactly like "take off vibration" which is where your output shaft and pinion angles dont match up causing the u-joint to rotate in an unatural way, which makes a jaunting vibration that feels kinda like you driving on tractor tires

 

Try downshifting the automatic to 3rd or second, depending upon what speed you were at climbing the hill. It does sound like the engine was "lugging", if your speeds were slowing. This is not good on an engine. This is why they have a "2" and a "3" as a selector for automatics. As you already stated, you had the overdrive off (good), but going up a hill (even if it is a small incline) with about 2000 pounds that you mentioned may have lugged the engine just a bit. Raise the RPM's by downshifting to 2nd gear.

Unless it has to do with a driveshaft not in alignment with the rearend deal....I've not experienced that unless the truck was lowered or raised.

 

no the truck is not lowered or raised as of yet, and as far as the engine lugging it wasnt i was pulling the hill at about 60 65. if the pinion angel is off due to a small load like this what happens when i have to haul something heavy?

 

its just what it sounds like, i have never had anyone come in and complain of an issue with like this with the new f-150, mostly new c1500's. you were running about 6500? thats right at your rev limiter, thats possible what you felt