vibration, driveline

02 TRD 3.4 auto. extra cab. Two piece drive shaft.

A while back I had the rear most u joint replaced. Most of the vibration is gone.
The carrier bearing was replaced earlier than that.

Still suspecting a drive shaft problem, I am trying the "field balancing" procedure of jacking up the truck rear end and holding some chalk up to the spinning shaft. At the moment I am working alone so it is running at idle mostly, with the rear diff locked.

I can see it is "wobbling" and the chalk mark indicated the heavy side. But before I start messing around any further, I noticed the replace ujoint zerk does not line up with the others. Is that a problem? I had a shop, reputable, install it. Did they do it wrong?

Also, the drive shaft rear section has some rust crust, some seems to have flaked off.

I tried getting a quote from a balancing shop (50 miles away, closest) but got no answer.

New shaft simplest solution? Good after market available?

 

Is your truck at stock height? Any aftermarket lifts?

When I had a vibration it was due to the pinion angle of the rear dif. It was corrected with shims to help 'level' out the angle from rear dif up to your driveshaft.

There's a nice thread where the angles and geometry are explained in more detail:
may or may not find useful

https://www.tacomaworld.com/threads/drive-shaft-vibrations-solved-step-by-step.244535/

 

This might help.
https://www.drivelinesnw.com/part-trouble-shooting/vibration-analysis/

 

This is a nice demonstration of changing driveshaft angles and their effects on rotational speed.
I encourage anyone to know this stuff BEFORE getting a lift

https://youtu.be/Idk3BVDVHq4

 

Stock height. No lift. Is the pinion angle an issue for stock?

 

I would think it’d be just fine stock.
Unless maybe your rear leafs are saggin a wholeeee lot

 

While chasing this problem I noticed the new Timken center bearing I put in less than a year ago seems to be sagging a bit. I thought the rubber was too soft when I put it in, but, the DANA was not available at the time and I was pretty sure the original was shot.

At this point I am tempted to replace it before going any further.

Is there a current dana/spicer part number? 2002 4WD TRD 6 auto.