The diesel engine's bolt pattern does not accept the GM 350 turbo trans. But it did use a GM manual transmission in its history of being in S10 pickups. That transmission was the T5 5-speed manual. But, to use that transmission you need the diesel specific bell housing that allows for the T5 transmission to bolt up to the C223 diesel engine. Don't think a GM 350 turbo trans could be made to work. May be a larger transmission than what the diesel usually saw anyways. The 81-82 Chevy LUV diesels never came with an automatic transmission from the factory, but starting in 1983 the same truck the Isuzu PUP received a 3-speed automatic transmission that was an option up to 1986. A diesel automatic pickup is rare to find though, but that would be your best bet if you wanted to change to an automatic trans. If you were interested in buying just that transmission heading over to
http://www.car-part.com and searching for one may really help. Hope this provides you some help.
Salvy