* SM465: A heavy-duty manual transmission.
* TH700R4: A 4-speed automatic transmission.
* TH400: A 3-speed automatic transmission (less common in '92).
To know for sure which transmission is in *your* specific truck, you'll need to:
* Check the VIN: The Vehicle Identification Number (VIN) contains information that can identify the exact transmission. You can decode the VIN online using various VIN decoder websites.
* Look at the transmission itself: The transmission case usually has identification markings cast into it.
* Check your owner's manual: If you still have the original owner's manual, it will specify the transmission type.
Without more information about your specific truck, it's impossible to say definitively which transmission it has.