Vibration on deceleration

Good day all. I've got a bit of a problem that I'd like to nip before it becomes a disaster and any help from people more experienced than me would be appreciated
My truck is a 2001 tacoma trd, 3.4, 4wd, with 329k miles, running strong and good.
I was on a trip in the mountains this past week so a lot of engine braking and I noticed that whenever the truck is decelerating in gear, it vibrates. The vibration seems to be worse at lower speeds, but it happens at any speed and in any gear. If the hill I'm going down is steep enough to cause acceleration or to maintain speed, it doesn't happen, and if I so much as tap the gas pedal, the vibration stops, so the problem is only upon deceleration.
And it should be noted that I'm not hitting the brakes at all when this is happening, so no rotor problems causing the issue.

Anyone with any experience or tips would be greatly appreciated

Thanks in advance

 

Ujoint

 

Agreed. I had a similar problem and it turned out to be a u-joint on my driveshaft. Here's a video on how to check for a bad u-joint.
https://www.youtube.com/watch?v=OVC76dSBNnY&feature=emb_logo

 

Welcome to TacomaWorld
Ujoint
Gotta lube them zerks at oil changes
It's a 4WD man

 

Thank you all.
I will be checking that out tomorrow.
While I'm there, I suppose I should check the center drive shaft support.
Any tips or links regarding how to do that would be greatly appreciated

 

If the rubber looks ok, check for play and/or roughness in the bearing.

 

I bought all new ujoints and a carrier bearing. Sent them in to the shop my truck was at. They greased the existing ujoints and replaced only the bearing. Decel vibration is gone.

 

The CB normal play is 1/4 to 3/8"
1/2" and over is worn out Replace it.

 

My 2006 2WD 4.0 is vibrating when decelerating from 40-30 like clockwork, I think I can notice it at other speeds, but it's pretty noticeable every time from 40-30, is this likely my issue as well?

 

Check your u joints for play. That'll tell ya.

 

yep u joints most likely. Had this happen to me last year on my way back from my Utah trip. About a 11 hour drive from CA to Utah then hit some trails out there for 3 days then drove to AZ flagstaff and then back home to CA. On the way back home from AZ was going up a hill on the 40 and started noticing some vibrations and boom one of the u joints failed. Had to drive back home on the front wheels.