New guy question, 86 GMC

[learpilot]

Just bought a nice 86 GMC sierra with only 47k, new looks and drive like it too. The only "problem" is it has the 3 speed auto trans. and I would have prefered one with an OD. My question what year donor trucks could I get an OD trans from or is the another way to achieve the same results? Thanks

[truckngrizzly]

yea you can look in most of the suburbans and trucks from 87 to 81 cam with a 700r4 that had an over drive. the only other part you will need from truck is the indicater gauge that is at the bottom of the gauges. it jsut unbolts and will replace the 1 u have now. then youll be able to know when your in overdrive.

[bad_gmc]

is it a turbo 350 or a turbo 400 tranny. i have a 87 gmc with a 700r4 but i would like to have a turbo 400.