2008__XL

Is yours a supercab? I've read somewhere about a weight that's placed on the rear of the frame from the factory that is supposed stop harmonic vibrations. Some had issues with it and I remember there being a TSB some years back.

I think it was called a "frame dampener kit." Not sure if that'll help, just trying to throw out ideas.

TSB 04-25-07

4aredneckwoman

No just reg cab with the 1/2 doors....Im thinking maybe tax time, LOL, prob June for me, Self employed, always go for the extensions....Ill buy me a new truck, sell it with disclosure. Im sure a lot of these farmers here wouldn't care. It'd be a great truxk for running to town and carrying small loads, day to day stuff. I only care because of highway driving. I have no tire wear, have had everything checked and repaired. It is just beyond frustrating.

2008__XL

my question was for the original poster.

TheOldRaker

I do have a super cab. I'll look into this kit.

I also checked out the vacuum lines today. It looks like that IWE Solenoid Part had been replaced. The one near the passenger side behind the battery on the firewall. I jacked the truck up, spun the front wheel in 2wd, it rolled correctly, then engaged 4wd, and the front wheel wouldn't turn, so it looks like everything is good with the vacuum lines. Outside of pulling the bearing off to look at the 4wd hub, I'm gonna say this isn't the problem.

While I had the truck jacked up today, I did a visual/physical inspection of the driveshaft, and the front U Joint on the rear driveshaft has some play in it. It doesn't look as bad as some of the examples i have seen on youtube, but it's where my head is at as far as first thing to try fixing. It's also the 07 model driveshaft, so I should be able to rebuild the U Joint myself. I read somewhere that the later models, like 09's, were a bit more difficult to rebuild.

That's the update for now. I should have taken a pic, I'll try to remember to take some pics when I take it apart. Thanks for the help so far, hopefully we can figure this out.

brokenarrow

I went down the driveshaft path as well. I ended up taking mine off and taking it into a driveshaft shop. They were able to check the u-joints and spin balance the driveshaft as well. It turned out that mine was perfectly fine, so they only charged me 15 bucks. If there's play in the u-joints, this is definitely something to investigate further.

Keep us updated! Good luck!

harricanfloyd

while it was up on jacks, did u put it gear and watch the rotation.... Could have a slightly bent axle shaft....never know

TheOldRaker

I didn't do that. My thinking is that if the Ujoint has a bunch of play in it, I may see something that looks like an out of plumb driveshaft, but could just be the driveshaft off center because of the Ujoint. Also, I was thinking of after rebuilding the Ujoint, taking the driveshaft to a local shaft guy, to get it inspected as well. People say that doesn't cost much.

On a maybe related note. I just got a transmission malfunction code the other day as well. I pulled a code, but I forget what the code was. I'll post the code next time I turn the truck on. If this turns out to be a bigger transmission problem, I'm not gonna be a happy person..

harricanfloyd

Joints will not likely "look" bad but can be troublesome. It sucks you haven't found the problem yet...especially with all the work done. If and when u do pull the driveshaft, clean the mounting surfaces. Usually, they are marked before they go back on...so the dirt stays in the same place lol. Yeah, the car on jack stand thing.....Old guy came to get me in his waiting room... "See, this is why I hate chain stores....nobody gives a crap" When I looked, he had the car in gear. My right rear wheel was waaay bent. I had the wheels balanced 2 times before and if bothered me that no one told me. But anyway, Good Luck, I hope u solve the problem!

EricNCSU1204

My Fathers '04 F150 crew cab 4wd is having the same issue as the OP's. We think it may be the lower ball joints. Will post if they are replaced and it solves the issue for us.

STSCDave

I have had a vibration at 54 mph since I bought by 07 regular cab 2wd a couple of years ago. New tires, plugs, wires, all kinds of other stuff done. I just don't drive at 54 and it is fine. Now that I think about it, when I am towing with a few thousand pounds back there I have never noticed the vibration.