[HO455]

Sorry for all the questions but they will make answering easier. The factory 1/2 ton coil spring driveline must move forward and aft as the rear axle moves up and down when going over bumps. This movement is absorbed by the yoke at the transmission. The yoke at the transmission is longer to allow for this movement. The factory carrier bearing rubber ring flexes with the movement. When a truck is lowered many times the rubber is constantly pushed beyond its design limit and that can cause the bracket to fail. Not to mention the lower quality of the aftermarket units available today would not pass GM's quality standards.
A 3/4 ton coil spring truck has a different style of driveline. The aft section has a splined slide that allows the for and aft movement to be absorbed there. The carrier bearing is much more robust and it holds the forward piece of the driveline solidly with very little movement.
The 1/2 ton style is cheaper to install which is why GM used it but it is not up to the task on a heavily loaded truck starting from a dead stop on a hill. So a more robust system was needed. The same was true of leaf spring trucks. When the axle wraps up the springs it causes more movement than a 1/2 ton coil spring carrier can handle.
If you convert to the 3/4 ton carrier bearing without using the 3/4 ton style drive shaft it is likely you will continue to break the carrier bearing.
The low cost method would be to add addtional welds a new carrier mount to make it stouter. When you installing it you need to have the truck sitting on the wheels at ride height. Then when you install the carrier the rubber bushing must be at rest. It cannot be preloaded in one direction. The carried mount holes may have to be elongated.
If you are running air bags then I would recommend using an aftermarket billet style carrier and having a slider installed on the aft section of the driveline.
Here are photos of the driveline I converted my C10 Burban to and the one I removed. There is more information if you are interested in my WMB thread below pages 13 & 14.
I hope this helps.