vibration at various speeds

I've been noticing a vibration that is very low pitched at lower speeds <40 mph and is mostly a constant sound. I've also had a vibration between 60-75 mph on the highway that shakes the interior pretty well. A brief history of the past few months:

- got new tires put on with an alignment
- installed new CV axle on the driver's side
- installed the ECGS front diff bushing for 1st gens, similar to this link: http://www.tacomaworld.com/forum/2n...nt-differential-bearing-vibration-thread.html

My old bushing was giving the rumble strip sound like that link discusses. That definitely went away. Now I'm wondering if I have one of three possible problems:
1) tires are out of balance? Easiest fix
2) the CV I got from Napa is bent...can this happen?
3) the new front diff bushing is vibrating for some reason? This one would be hard to diagnose

 

Is your truck lifted?

 

No lift, all stock.

 

Bump...any help on this?

My main concern is that right when I let off the gas pedal, I can hear/feel a grind or rubbing sound in the floor. One the u-joints had slight play, replaced it but that didnt help. Is this a symptom of a bad carrier support bearing?

 

Sorry this was in the wrong forum, should be in 1st gen

 

actually I wonder the same I have a 07 prerunner and it doesn't have a carrier I did notice a one of the bearings on my u-joints was missing a sleeve but not convinced that is the source. Mine makes a vibration mostly when I let off the accelerator and gets worse when letting off going down hill. but I can't feel it in the floor, on the steering wheel, or even in the shifter. recently changed oil, trans fluid, and rear end with no evidence of wear and no change in vibration. Haven't heard any noise to do with axle wrap as described on the site. but the rear does sit lower than the front.

 

Mine is a mystery. Not getting worse yet, happens at higher speeds with overall truck vibration at lower speeds. Trying to change carrier bearing first.

 

Mine is an 06 DC automatic trans with a 3 inch Daystar lift and blocks on the rear. It just started vibrating at about 35mph, then again around 45 mph, and again above 55 mph. When I let off the gas the vibe goes away. Also, if I just sit still, put it in neutral and rev the motor up - nothing vibrates. So I'm thinking trans, drive shaft, or rear end. Any ideas? What should I look at/for, etc????