Bad Carrier Bearing?

So I have been driving my mazda for a while now, 1993 B2200 Short Bed Standard Cab 144k miles lowered, and I think my carrier bearing has failed. When it is rolling the truck is smooth and quiet but as soon as I accelerate or touch the gas it get a horrible thwacking/ cluncking noise, almost like there is a large ziptie on the driveline hitting the frame. I put the truck up on stands and checked the driveline, it is not hitting or contacting anything and "feels" tight without any excessive play. I ran the truck through all gears on the stands and the noise isnt there. Only does it when the truck is on the ground. Any ideas? Am I on the right track thinking the carrier bearing is bad? Any input would be greatly appreciated.

All gears? Only forward?
Have you checked the transmission mount.

Yes all gears and I didnt think to check, just did, does not do it in reverse. I will jack it back up and take a look at the trans mount, rear mount right?

I don't think a SWB truck has a two-piece driveshaft.
(no carrier bearing)

From your description it sounds like the u-joint is on the way out. You can climb under the truck and wiggle / rotate the drive shaft to see if it is loose where it bolts to the differential. Since you can put it on stands, do that, and then apply the emergency brake to simulate the wheels on the ground and then run the drive shaft in gear.

My .02.

Jacked the truck back up and took a look at the trans mount, its pretty thrashed, dryrotted, and cracked. I will be replacing that tomorrow $23 at Napa. And yes even swb Mazdas have a 2 piece driveshaft and carrier, kinda odd but they do.

Replaced the trans mount, no change in sounds/problem. Took a closer look at the driveline and carrier, it doesnt look so great. Just going to pull the driveline and have it rebuilt.

New driveline in and sounds are all gone, u joints and carrier were pretty hashed. Got a new modified driveline in that has normal easily replaceable u joints, glad to have my truck back!