Vibration Problem at Certain Speeds

Hey Guys! I am pretty new to TW but am loving it and finding it very helpful.

I have an 05 Tacoma PreRunner with a 6" front lift and a 4" rear lift and 285/70/R17. I understand with this build the truck is going to run a bit rougher than stock and I am fine with that.

The problem is:

I am a college student in Kansas and had a 3" lift at the time running the same tires. I had no problem with vibration/shimmy driving around up there. I drove back home to Texas for this Christmas break which is a good 860 miles. During the 2nd half of the trip I noticed that around 25-30 mph there would be a quick shimmy and then around 35-40 mph there was a longer vibration that felt like the whole truck was shaking. I also noticed if I accelerated faster it wouldn't happen most of the time than when I accelerated at a slow steady rate. Once I got home it continued and I upgraded to a 6" lift. The problem was still occurring and appears to be getting worse. I have an appointment in a few days to align the tires and hope this will do the trick. But I find it weird that it started before I put the new lift kit in and didn't occur until the long trip back.

If the alignment doesn't fix the problem does anybody have an idea of what it might be or the next step to take?

Thanks Guys!

 

Could be your ujoints or carrier bearing

 

I agree ...... Carrier and/or u joint

 

Alright thanks guys!

I think I'm going to replace the ujoints first and see if that fixes it and if not I'll then replace the carrier bearing.

 

U joints. had the same problem last week. I replaced them both. Problem solved

 

you know this is gonna sound weird.... but i had bad vibrations as well at highway speeds. tried to figure it out for months. tried carrier bearing shimmed custom with washers at different levels to see if i could make it work. 3 shops kept doing alignments. but was at local Hot Rod shop and the mechanic there is a mad scientist. one of those who think outside the box. so he jacks up my back end and tells me to put it in gear. It was a sepparated tire. 3 shops were gonna put a new driveshaft in, new ujoints... etc etc.

 

I replaced the carrier bearing and checked the ujoints and they felt fine and after the alignment the vibration still occurs.