aka "the chunk", "the pumpkin". It is the center part of your rear end. When you remove the axles, you can remove gears, carrier, bearings, as one piece. That piece can be bolted into the housing of your existing rearend (from which you extracted the differential of your torque tube rear end,) which means you can look through the housing because the back cover is off and you removed your torque tube r/e from the front. The third member bolts in from the front, you re attach everything inside, put on back cover, fill w/ gear lube and you are ready for a regular driveshft with u-joints.
With all that said, I opted for a complete 89 Camaro 3.42 rear end for the gearing and brake parts and it is the right fit. I had to grind the spring brackets off and weld in "normal" perches, but that was it.
