* 700R4 (4L60): This 4-speed automatic was very common in that era.
* 4L60E: An electronically controlled version of the 700R4. The "E" denotes electronic control. This was also frequently used.
* SM465: A 4-speed manual transmission. Less common than the automatics.
To know for certain what transmission is in *your* specific 1994 Chevy 1500, you'll need to check:
* The vehicle's identification number (VIN): A VIN decoder can tell you the transmission code.
* The build sheet (if available): This would explicitly state the transmission.
* The transmission itself: Look for a tag on the transmission case that indicates the model number.
Without knowing your truck's specific details, it's impossible to say with certainty which transmission it has.