what trans do i have?

[imfixinmopars]

i have a 1986 gmc dump,single wheel,366 gas like a c6500?,there are no emblems..what trans would this truck have? its a 5 spd manual.it shifts hard and its difficult to get it in 3rd gear,and might be looking for a different one.any help is great,mike i know i have to look at the trans to see if it has any numbers or tag info but its not here right now at the shop.