So here recently i started getting this vibration while driving. I figuredbout that it only occurs at low rpm(1250-1700 roughly) and goes away as i pick up speed and rpm.

Im suspecting its a bad u-joint but at first i suspected bad engine mounts abd tranny mount. Upon installing tranny mount i realized i just might be an idiot for thinking that and one of my friends suggested that it might be the u-joint..

Suggestions please?

 

I would check to make sure you don't have a tire out of balance or maybe one that has uneven wear.

 

U joints are fairly easy to inspect. If you look at them and see red rust or powder around the caps, its a sign that the u joint is failing or toast.

I just replaced mine 2 weeks ago

 

i will check on the caps. but i also have a tire with uneven wear up front. but i don't think that would make a vibration with differences in RPM..

 

Not so much to do with RPM's as it does with the speed you are traveling

 

Thats what i thought. But its barely noticeable in 1st and 2nd because those are quick gears. But in lower rpms in 3rd - 5th its very noticeable until i reach around 1700rpm.

 

It wouldn't be very noticeable at those low speeds.does It gradually gets worse up to around 45-50 mph then start to smooth back out above that? Do you feel vibration in the steering or more in the seat and floor board?

 

Its the seat and floor board. Speed really isnt a variable. Its just the roms im driving at. No matter what speed or gear 1500 or less and the vibration is there. I checked today and its normal at 1700.

 

If its rpm then its driveline related. Grab the.drive.shaft and try to twist it. Any movement means bad u joints. If its good try a coast down test. Dive up past the speed and coast till you hit.the target rpm. See if you get that vibration. Also try a low gear and run up with heavy throttle through the target rpm. That keeps torque on the driveline. I have to check my book so I don't tell you wrong but this will eliminate some sources depending on when the vibe hits. You can also eliminate tire issues by rotating them and see if its better or worse.

 

It sounds stupid.... But if Its not a u-joint, get your tires reballanced.

I just got new skins on my truck and when i took it out for a test drive, i didnt feel anything wrong until i was up at 60mph... i bumped the speed up until the truck governed out. By this time, i was getting a 3/4 inch movement shaking on the steering wheel.

Took it back, reballanced the tires... 1/16 inch shake... Livable when the truck is going much faster than what highways are legal. But the tech tried to get me to align the tires, i said, the truck doesnt pull to one side it just shakes