I have a stock six engine and trans with the top shifter, would like to convert to a trans with a overdrive. What trans is a good choice that would have a top shift with a overdrive?
S10 T5 is the popular choice. Do a search on here, there are links to adapters and parts needed. 3/4 tons have 1/2 open driveshafts, so you can do this without swapping rear ends.
