alright so yesterday i got stuck in a little bit of mud, i put itr in reverse... eased on the gas... started moving then all the sudden BAM!! no more reverse... so time for a new transmission. i was wondering if anyone can help me out on what kind of transmission is in this truck so i can start looking in salvage yards

1990 gmc sierra ext cab regular box

if you need more info ill be glad to give it to you its actually my friends truck but i messed it up therefore i gotta pay

 

Alright lets see. On the bottom of the Glove box door it will show a bunch of 3 digit codes. Probably around 70-80 different codes. Look for any codes that start with an M and I'll tell you what tranny you got

My 92 with the 5.7 has a 700R4 Tranny which I would assume yours has

 

alright thank you very much

 

Yeah, if it's the original type transmission (meaning no one has swapped it for a different one in the past) than it is definitely a 700R4.

 

Thats what I was thinking, but I was unsure of what engine he had

 

btw just when im at the salvage yard, finding a replacement, obvioulsly i cant drive the donor truck to see if its fine, is there any visual signs to see if it a good repalcement transmission?

 

Its gonna be a risk when you are gettin a used one. I took that gamble when mine went out. Paid 800 for a used one. Turned out it didnt work on my truck. The pump needed to be rebuilt and needed a new torque converter. Extra 500. Shoulda just got mine rebuilt for a couple hundred more. Lesson learned.