Corvette Transaxle

In keeping with the low buck nature of this project, I never intended to use an XTrac 195 gearbox, which was the original transaxle when the car was raced. The car came with an XTrac case, but it was empty inside, no gears, nothing. For years I've been trying to figure out what to do. I considered other racing transaxles, but there was nothing cheap that could handle the torque of an LS Chevy.

I then went on a years long Internet journey to find a street car transaxle that would work. It would have to physically fit within the car, be readily available and be able to handle a lot of power of a torquey V8. The short version of the story is that I settled on a C5 Corvette transaxle. Those in the know will point out that it is not a real transaxle per se, it's really a regular Borg-Warner/Tremec T56 gearbox with a special tail housing that lets it bolt directly to a differential (see Figure 1.). It looks like it is going to be a viable solution as it fits my criteria with only a couple of adjustments to make. So full of optimism, I bought a used Corvette T56 off of the Internet and a differential from LKQ.

Figure 1: Corvette C5 transaxle. Notice the shift linkage coming out the front of the gearbox above the input shaft. Image courtesy of Oards Automotive Hub.

The Corvette transaxle is not a bolt-in solution though. As the Corvette is a front engine car, the front of the T56 is not set up to bolt directly to the engine, it's configured to accept a torque tube. And because the driver is so far forward, there is a specific shift linkage that comes out the front of the gearbox, through the area where the clutch normally sits (the Corvette clutch is up front attached to the flywheel), and runs back up the torque tube to get to the driver. I have already started attacking the first hurdle with the front of the trans. This is actually a pretty easy fix because there is so much interchangeability with the different versions of the T56. In this case, you can replace the front plate on the Corvette trans with the front plate from a Camaro. Then you just need a regular bellhousing to connect everything to the engine (see Figure 2).

Figure 2: Transaxle mated to the engine.

I haven't started working on the shift linkage problem yet, but I have a solution in mind using parts from the Cadillac CTS-V configuration of the T56. I'll talk more about that when it's closer to actually happening.

So there is everything bolted together for the first time. The whole contraption looked really long when I was putting it together, but as you can see in the background, the Corvette trans is actually much shorter than the original XTrac gearbox (see Figure 3). And importantly, the half shaft location is within an inch of the original location.

Figure 3: Corvette transaxle (foreground) vs. XTrac 195 transaxle (background). 

Now for the elephant in the room... how the heck am I going to attach the rear suspension?