No experience with the trunnion or other manual parts, but the ring & pinion has been the weak point in my years of automatic 8 3/4 footbrake racing. Stripped the teeth a few times. I had no issues with solid Spicer u-joints and steel billet rear end yokes even though they were for 7260 joints...
About 1/2 way down there is a drawing of an A-833 and notes indicating it got an O.D. 4th gear in mid-1975 for 318s and/6 which would make it likely available for the 1976 model year
.Chrysler A-833 four-speed manual transmissions —...
Wikipedia also shows the A-833 OD version being used from...
I'm pretty sure that the engine size would have an affect on the transmission options. A 360 was available through 1976, but I can't imagine a 3.09 low gear and/or O.D. with it. It wouldn't surprise me if 318's were the same, leaving just the /6.
Wheel hop is usually due to leaf springs wrapping & unwrapping. In other words, torque twists the housing up and turns the springs into an "S". Then they spring back and the cycle continues. As others have mentioned, stiffer springs and an adjustable pinion snubber can help. But shocks are...
You should get the gear ratio and tire height to help narrow down what you need. I only have a few gears for sale, but the chart in the ad should help you anyway.
http://www.forabodiesonly.com/mopar/showthread.php?t=294521&highlight=speedometer