* TH350 (3-speed automatic): This was a very common automatic transmission for that era.
* TH400 (3-speed automatic): A heavier-duty automatic, often found in higher-payload or heavier-duty versions.
* SM465 (4-speed manual): A robust manual transmission.
To know for sure what transmission is in *your* specific Vandura, you need to check:
* The Vehicle Identification Number (VIN): Decoding the VIN can reveal the transmission type. You can often find VIN decoders online by searching for "GMC VIN decoder".
* The Build Sheet (if you have one): This document will specify the options, including the transmission.
* The Transmission Case Itself: Look for markings cast into the transmission case. This requires some knowledge of transmission identification. A picture of the transmission case could help someone identify it based on the markings.
Without looking at your vehicle, it's impossible to say definitively which transmission you have.
