Vibration, but only under throttle

i read through many of the threads on the vibration issue that seems pretty common in these trucks. Since I’m about to do a suspension swap, I wonder if I should also replace the carrier bearing. My truck seems to get an annoying vibration anytime the truck is under throttle up to about 70 mph. Then it smooths our. It also seems better when I have a full tank of gas. I know I am running around on old, worn-out tired (going to replace them when I do the shocks) but if the vibration was coming from the tires, wouldn’t it always be present? If I’m going down the road at 40 mph I feel the vibration but as soon as I lift off the throttle, it goes away. If it was a tire issue, wouldn’t I feel it all the time at that speed, and not only when I’m under throttle? Is that a dumb question?

 

this is the first year i started having weird vibes in my truck
but its somewhat different than yours, my vibes are resonating through all the gears (MT) and only happens at 2.1k RPMs, it may happen higher but rarely do i go over 3k RPM
and the A/C must have also been on prior and turned off for this to happen (usually)
it does not happen anymore that there are cooler temps and no need for A/C
so its weird as weird can get i guess

maybe somebody reads your concern and sees mine and has seen both issues and can help us out!

 

@BossFan
Where is the vibration coming from on your truck? Towards the front, back, steering wheel? Sounds like your issue could be the carrier bearing and worst case u-joints. Get under your truck and take a look at the carrier bearing. If there is noticeable cracking or gaps in the rubber, then definitely replace ASAP. Be sure to mark your driveshafts before you remove them so that you align them correctly when you install them. You can also try to move your drive shaft around by grabbing on either end of the carrier bearing. if there is a lot of play, replace.

Another way to troubleshoot is to crab your Transmission handle or t-case handle when driving and during the vibration. This will also help give an idea of where to start looking.

New coil overs and shocks and tires will help a lot too. If you lift the front, be sure to replace the drivers side needle bearing on the front diff with an East Coast Gear Supply bushing. There's a really good youtube video on this. and a couple of threads on here.

I would also look at trans, t-case and engine mounts just for good measure. As well as ball joints, and any rubber suspension components. Since you are doing a lift, it wouldn't hurt to replace all of this stuff and not have to worry about it for a long time.

@GQ7227
I have been chasing a resonating vibe similar to yours but happens between 40 and 45 mph, I am thinking my drive shaft is out of alignment since its more of a drone/resonance rather than a vibe. The whole A/C on/off thing makes your issue kind of tricky. But i would say to go out and drive around on a smooth straight road and try to hold the rpm in the 2100 zone to induce the vibe and try to get an idea of where on the truck its coming from. Check different mounts and bearings and wear items.

Hopefully this helps. I am no expert by any means but have chased down and fixed various vibration issues on my truck with the help of TW.
You guys can also tell me to kick rocks! haha.
Good luck