Here's why it's problematic:
* Different PCM/TCM communication: The 1997 transmission will likely use different shift solenoids and electronic control strategies that are incompatible with the 1994 truck's PCM. You'll need to either swap the entire PCM/wiring harness (a massive undertaking), or find a way to adapt the 1997 transmission's electronics to work with the older system. This often involves custom wiring, and potentially a standalone transmission controller.
* Torque Converter: While the torque converter might *seem* interchangeable, there could be subtle differences that lead to problems.
* Input/Output Shafts: While the 4L80E generally maintains a similar spline count, minor differences aren't unheard of across model years.
* Speed Sensor/VSS: The speed sensor location and signal might be different, necessitating further electrical work.
In short, while it *might* be physically possible with significant fabrication and electrical expertise, it's not a straightforward swap. Finding a used 4L80E from a closer model year to your 1994 truck would be a far simpler and more reliable solution. A professional transmission shop specializing in older GM trucks would be the best resource for determining feasibility and cost.
