Excessive Driveline Vibration When Accelerating (Help!)

So my Tacoma developed a driveline vibration a number of weeks ago... and I'm completely stumped. It started out as a very noticeable, but not that awful vibration when accelerating in 3rd gear, and then drove fine at highway speeds. Then it became worse and started happening on 2nd AND 3rd gear acceleration a few days later, and one night it all of a sudden got so bad that it was shaking so violently on my way home at pretty much any speed that I decided to park it once I (felt like barely) made it home. I got underneath it the next day and determined my carrier bearing was shot (lots of play in all directions, I should add that I also checked the U-joints for play and they felt rather tight with minimal play) and the symptoms made sense, so I decided I needed to replace the carrier bearing. I have lots of projects atm so it ended up sitting for about a month and I just drove a different vehicle, until I finally ordered a bearing and put it in today. I bought the Spicer carrier bearing that I've heard lots of good things about on this forum, and I don't particularly believe it to be the culprit... but the vibrations on acceleration still persist with the new bearing installed.

One very interesting thing to note is that it did actually fix the problem to a small extent. The best way I can describe it, is that it's now the same way it was roughly a week before it started to go seriously bad and shaking at all speeds (so slight shaking in 2nd on accel, more prominent shaking in 3rd on accel, will go down the road at 45-55 alright). Another thing to add is that I'm sure its in the driveline because it won't do it if I'm coasting or shifting from 2nd to 3rd, but it doesn't really matter what gear I'm in that much either; if I try skipping 3rd (since it seems to be the worst at 3rd gear speeds) it still does it in 4th gear, just at lower RPMs.

Any help and input is much appreciated, I'm kinda at the end of the road with what I can think to try. I don't want to just throw parts at it as my bank account has taken some serious blows lately not to mention the waste of time... but I'm wondering if I should just try a new driveshaft or U-joints, even though mine appears to have very minimal play (feels like less play than my 03 Sequoia which drives great)? This has been very frustrating and I really don't want to take it in somewhere as I like doing my own repairs.

 

U joints as a next step. They can look good, feel free, but cause wild vibrations under load.

If you want to make sure putting the rear axle on jack stands and running it up to speed while watching the shaft will help visualize it.

 

Check to see if the driveshaft has thrown a weight.

 

I had this same problem with my ‘04 automatic. I was also sure it was the driveline bc I put it into neutral while driving and all the vibration and noise went away. It ended up being the Ujoints although the carrier bearing was replaced as well (305k on it). Are you hearing any noise when you reverse?

 

U Joints can be tight feeling but totally trashed internally. If they feel stiff, they are bad. They should rotate easily and smoothly in all directions when tested by hand.

 

U joints can develop play which is easy to check. U joints can freeze which is hard to check. since you have another vehicle to drive, I'd pull the shaft and send it out to a driveline shop. They'll replace all of the u joints and spin balance the shaft. You'll essentially have a new rebuilt driveline and if there's a vibe after that, you know it's not the drive line.

 

Thanks for all the replies, I'll have to see what driveline shops are around me that I could take the shaft to. Definitely makes sense for u-joints to be bad at 266k miles even though they felt fine by hand with shaft installed

 

A few of us have had our rear drums cause vibrations unrelated to braking. Swapping in a new set of drums might fix your issue if the driveshaft shows no issues after inspection.

 

I replaced my rear drums about 4 years ago with new ones, and the vibration also stops if I let off the gas pedal regardless of speed, so probably unlikely. Although that's definitely good to know, I've known about warped rotors causing wobbles/vibrations but never thought about the possibility of warped drums too.

 

Just wanted to write an update for anyone who was curious; I went to pull my driveshaft and noticed as I was removing it from the rear diff that the rear most u joint was absolutely shot. When I was loosening the bolts, the input on the diff rotated about a 1/2" and the drive shaft remained still. Not sure how I didn't notice that earlier when I checked... but anyway, I got a new u joint and just replaced the one that was shot, as the others were very tight still and moved smoothly. Put fresh grease in all of them and reassembled, drives smoother than it has in quite some time now.

 

Thats a great share. Thanks for the update.

 

Your post caught my eye. We have similar models. I was talking with my mechanic not too long ago about the exact same issue, only the vibrations I felt weren't excessive, but noticeable. Glad you got it resolved.

 

This was the smoking gun. You gotta disconnect the shaft to check the u joints unless they are totally shot.