* Transmission and Torque Converter: You'll need a suitable automatic transmission (the correct year and model will depend on the engine, but TH350 and TH400 are common options for that era C10) and a matching torque converter.
* Transmission Crossmember: The automatic transmission will require a different crossmember than the manual transmission. You'll either need to find one specific to an automatic-equipped C10 of the same year or fabricate one.
* Driveshaft: The driveshaft length will likely need to be adjusted or replaced to accommodate the automatic transmission.
* Computer/Control Module (possibly): While 1977 C10s were not fully electronically controlled, you might need to modify the existing wiring or even add a controller depending on the specific automatic transmission chosen and your engine. Some older automatics are purely mechanical.
* Shift Linkage and/or Cable: You'll need the appropriate linkage or cable for the automatic transmission's shifter.
* Fluid Cooler Lines: You'll need to install transmission fluid cooler lines, connecting the transmission to the radiator or an auxiliary cooler.
* Kickdown Linkage (Possibly): Depending on the transmission and the carburetor setup, you might need to install kickdown linkage to control the transmission's shifting under throttle.
* Floorpan Modification (Possibly): You may need to modify the floorpan to accommodate the automatic transmission shifter.
* Wiring Harness (Possibly): As noted above, depending on the transmission type, you may need to adapt the existing wiring harness or install a new one.
* Professional Installation (Highly Recommended): Unless you have significant experience with automotive transmissions and mechanics, it's strongly recommended to have a professional transmission shop perform this conversion. This is a complex job with many potential points of failure. Improper installation can lead to serious damage to your truck.
In summary: Converting a manual to an automatic transmission is a major project. It's far more involved than simply swapping out the transmission itself. The cost of parts, labor (if having a professional do it), and potential unforeseen complications should be carefully considered before undertaking this conversion. Get quotes from reputable shops to understand the overall cost.
