One of the main reasons that I was attracted to my C10 when I came upon it on Craigslist was that it was a manual transmission truck. I knew how easy it was to find a T5 overdrive transmission in the wrecking yard and what it would take to install one in a classic truck. They bolt right up to the stock bellhousing and require little, if any, custom fabrication to fit where the original three-speed once sat. A new clutch would bolt right up to the original flywheel and the stock linkage from the pedal to the throwout fork doesn’t care what’s behind the bellhousing. I knew the stock two-piece driveshaft would need to be replaced and a crossmember would need to be added to support the tailshaft of the transmission, but other than that, it would be as easy as a transmission swap can get.
The first task necessary was to sort out a decent transmission. That was easy as I already had a gearbox sitting in another project that I could borrow for the time being. That trans I had picked up years before for $125 in a Northern California junkyard. I would, however, need to replace it with something to support the motor in the aforementioned project so I made a quick trip out to the Pomona Swap Meet where I scored another T5, a World Class unit, for $200. It would also be necessary to swap out the tailshaft on the Camaro box with that from an S-10 (check out the January 2011 issue for all the details on this swap). With that done, I was ready to tear into the project.
Disassembly of the original parts and pieces was up first on the list, removing the original Saginaw three-speed, cast-iron bellhousing, clutch, flywheel, and assorted accessories. A quick bath in the degreasing cabinet and a coat of Summit Racing Cast Iron Gray got the bellhousing and throwout fork looking good as new, while the flywheel was sent over to McLeod Racing where it was Blanchard ground to remove any hot spots and imperfections. While there, I also picked up a new clutch disc, pressure plate, and throwout bearing. Leaving McLeod’s Placentia shop, I stopped off in nearby Anaheim to pay Classic Performance Products a visit and picked up the last piece of the puzzle, the transmission crossmember.
With everything I needed to start the swap, I tore into it with earnest; that heavy, cast-iron transmission giving way to a sleek, aluminum overdrive. Once underway, I ended up making the transformation in less than two days, a perfect weekend project. Anyone who’s driven a truck with a column-shifted manual transmission can tell you it’s not exactly a sporty venture. The location of the shifter and the shift pattern usually associated with these setups don’t make them akin to driving something with paddle shifters. Upgrade the transmission to something like the T5 with its closer ratio and move the shifter to the floor, and you’d be amazed at just how much the experience changes. Not only does driving that old hauler become a more sporty affair, but the closer ratio allows the motor to remain in its “sweet spot” longer and the Overdrive Fifth gear means no more getting passed by fowl-hauling 18-wheelers on the highway. CCT
Gear Ratio Comparison:
| 1st | 2nd | 3rd | 4th | 5th | |
| Saginaw | 3.03 | 1.75 | 1.00 | ||
| T5 | 2.95 | 1.94 | 1.34 | 1.00 | 0.73 |
