I have a 84 k5 with a th350 in it, and it seems to have a hard time in reverse when it has sit and cooled down. It has been doing this for the past year, so it not like it just started. It shift fine and you feel it engage, but it seems that you need to give it a lot of gas to move it in reverse. It also seems to do better when you drive around and the transmission has warmed up. Do you guys have any idea to what might be causing this. The transmission was rebuilt by the po, at least that was what he said. With what the po said to me, it might have less than 5000 miles on it since rebuild. The transmission doesn't have any problem going forward, runs very smooth through all gears. Any ideas?