* TH700R4: A 4-speed automatic overdrive transmission. This was very common.
* 4L60E: Another 4-speed automatic overdrive transmission, though this one is electronically controlled. It became more common in later years, so it's *possible*, but less likely than the TH700R4 in a '93.
* SM465: A 4-speed manual transmission.
* NV3500: A 5-speed manual transmission (less common in a 350 application).
To know for sure which transmission is in *your* specific truck, you need to:
* Check the owner's manual: If you have the original, it will list the transmission.
* Look at the transmission itself: The transmission case usually has identifying numbers cast into it. You can then cross-reference those numbers online.
* Check the VIN: The Vehicle Identification Number (VIN) contains information that can help identify the transmission. You'll need a VIN decoder, though.
Looking under the truck at the transmission will be the most reliable way to identify it visually.
