OK, so I'm driving home today in the snow and started to slide around so I put my truck into 4hi and I got a lot of vibration. I just got a 6" lift, 35s, and 4.56s and I have had them a little over 500 miles. Has anyone had this problem, can anyone tell me what the problem might be? Thank you.

 

A "vibration" isn't the same all the time. I see a lot of JR members just hoping to figure out things on this site without looking first. They post the problem, then want an answer to their problem. So let's dissect your problem. You have a 4x4 that we assume is a Ford. No engine size, model year, transmission. Other than that little bit of missing info, we know that you have a recent lift kit and gears. I suspect this may be the first time that the 4x4 may have been engaged since the above changes, I may be wrong. Can't tell from your previous description. So as to that fact, I guess you could have an out of balance crankshaft, a harmonic balancer pulley coming apart, a loose torque converter, various engine mount issues, U joints going bad, faulty belt tensioner, water pump, loose belt, etc, etc, etc.

 

OK, sorry for the lack of info. I have a 2007 5.4l xlt supercab. It has about 13,500 miles and I have put almost 600 on the new gears, lift, and tires. The problem I'm having is what feels like a vibration when I put my truck in 4hi. This happens when I go over 10mph. This isn't the first time I have used the 4hi since the upgrades, but it's the first time, I have gone over 10mph. I don't have the problem when in 2hi or 4L. So I took my truck back to the shop and they drove it and they said that some of the 2003 and up F150s came from the factory with an unbalanced driveline. Does this sound familiar to anyone? The upgrades I've done include 6" lift, new 18"wheels, 35s and I previously had 3.55 gears, but then upgraded to 4.56s. I also had a small amount of fluid leaking from the rear differential and they said that I had a pinion seal leak. So the advice they gave me is to put another 500 miles on the gears, and they would order the pinion seal and then do everything at once the driveline balance and the pinion seal as well as replace the front and rear differential fluid with Royal Purple. Any advice?