I just recently got a 1990 chevy suburban and i need to know the transmission that came in it! so i can replace it.

Im pretty sure it has a 700R4, sounds like you might have a valve body failure, might be a pan fix, it shifts hydromechanically as opposed to a newer 4L60E (essentially next gen 700R4) that has electronic controls.

hey, i had the same year also wondering, i lost reverse... then 4th/overdrive, then third then second if i kept it in drive when it whent to shift up it was like hitting nuetral. you think it was shot or an easy fix?

Sounds like a loss of line pressure or a really screwed up valve body, can you go through the gears by moving the shifter manually?

lol no i tried that too, once overdrive and 3rd stoped working i kept it in second manualy that way it wouldnt try to shift up into nothing, that would be cool if it was line pressure but the engines out of it now anyway