1994 chevy silverado 2500, no get up and go

A through tune up is probably in order...plugs, wires, fuel delivery system...the entire gamit. The tranny should not be the problem unless it is either bnding or slipping. Also at that age, your compression could be waining, hope not, that would be an upper end rebuild. Have you checked compression, valve leakage or cylinder blow-by would cause a loss in power as well. A lot to check, and at almost 20 years old, could be a combination of issues...involving wear, but first, and cheapest, tuning and diagnostics. Hope this is helpful...Goood Luck