Hey folks im new to the forum so forgive me for my future mistakes,, I have read tons of forums on this subject but none of the others i ha e read about have seemed to have the same issue as me. I have this recently purchased 93 dakota 2wd with a 3.9 an auto, when i bought it the overdrive did not work, i ran the codes and it had a speed sensor code, i replaced the speed sensor and got overdrive to work but it didnt work properly, i have checked wiring, fuses, relays etc (did not check any wiring with a meter) so it now has new radiator, thermostat, coolant temp sensor(for ecm not gauge) TPS sensor, speed sensor and i cleaned the air intake temp sensor and have adjusted the TV cable several different ways,my OD switch and cruise control work as they should however, the truck shifts 1-3 as it should all the time no matter what but it only goes into overdrive when the ttuck has sat all night or all day like when i let it sit at work all day then get in it to go home, when i first hop in and take off it shifts 1-3 then overdrive like a brand new one but after i get about 20-30 miles i lose overdive, now and then i can get it to kick in again if i run it up to about 3500 rpm but if i let off the gas or apply the brake to quick it will kick right back out, almost like something is getting hot and starts to fail, i am at a loss please give me your input thanks.