* 4L60E: This 4-speed automatic was very common.
* 700R4: A 4-speed automatic, though less common than the 4L60E in '94.
* SM465: A 4-speed manual transmission.
* NV3500: A 5-speed manual transmission.
To know for sure which transmission is in *your* specific 1994 Chevy Silverado, you need to check the vehicle's identification number (VIN) or look at the transmission itself. The information will be on a tag on the transmission.