* 4L60E: This is the most likely candidate. It's a 4-speed automatic transmission.
* 4R70W (less likely): While less common with the 4.3L in that year, a 4R70W (a 4-speed automatic) *might* have been an option in certain configurations.
To know for sure which transmission is in *your* specific truck, you need to:
* Check the VIN: The vehicle identification number (VIN) will contain information about the original specifications, including the transmission.
* Look at the transmission itself: The transmission case usually has an identification tag.
* Check your owner's manual: If you still have it, the manual will list the specifications of your truck.
Without more information about your specific truck, it's impossible to say with 100% certainty which transmission it has. The 4L60E is the most probable answer, however.
