DTC P0756 lay term
 

So, I had my transmission fluid changed and had problems immediately following. Transmission was in limp mode and spitting out trouble codes. If you don't know what limp mode is it is like trying to take off in 3rd gear from a dead stop with a five speed manual tranny. I "limped' it back home and put my code reader on it and got DTC P0756. The next morning I took the blazer back to the lube shop and they sent me to a transmission shop. Before my car was on the rack at the tranny shop the owner told me what he thought it was.

he had run into it a lot before and explained the selenoids sometimes are broken when replacing the pan (especially, to those that haven't had the pleasure of removing and replacing the pan before). There is very little clearance and the selenoids are mostly plastic from what I saw. So, it isn't difficult to screw one up. long story short. They replaced my shift selenoid the lube shop had broken problem solved.

Note** while everything was apart I asked the guy what the cost was on the parts he said the selenoid was $34 I asked him of he would replace the other too since it was already apart. He did and only charged me for the second selenoid.