transmission shifting problems

just bought a 96 tahoe knowing that it had a "transmission problem"...drove it and noticed that i had no tach/speedo...intermittently it would turn on. later i noticed i was stuck in a high gear (3/o'd). so i manually shifted, but only 2, 3 and o'd worked. shut off the vehicle and speedo/tach started working (and stayed on) and was able to drive with all gears (1, 2, 3, o'd). And under WOT, shifted into 1st fine without slipping. this an electrical problem or mechanical? any suggestions?

*check engine light is on. had not had the chance to get codes scanned...

Welcome to AF, sounds like a speed sensor problem in the trans, get it scanned to pinpoint the problem.

ok scanned for codes today..

P1860
P1864
P1886

upon clearing codes and starting the vehicle, MIL immediately comes back on. no tach, no speedo, no prndl lights, check guages lit, and transmission stuck in 3rd if in O'd or D, so have to manual shift. intermittently tach/speedo and lights will work, and than transmission will shift fine

FIXED!!: faulty ignition switch