i have a 700 behind an ls1. it was rebuilt and had less than 1000 miles on it when it lost forward gears. it broke the sun gear, and had some sticking valves in the vb, and one valve that was frozen in place. after cleaning/replacing the valves, it worked great for a day, then i assume the governor got stuck and lost 1st unless i put it there manually, thats when i noticed there is no 1-2 manual shift. what could cause this, was the valve that was completely jammed supposed to be like that.

 

Sounds like the valves are sticking again. If you clean the valves, make sure you use a file to get rid of the "high spots" on the valves and "DO NOT" use sandpaper to clean them up as this will "round off" the sharp edges of the valves and they will freeze up in short order. Put the valve inside the aluminum bushing without the spring and hold your finger at both ends and hit it sideways against a wooden bech till the valve moves freely, and take a file to the aluminum bushing to get rid of any high spots so that it will re-install easily.

 

i drove out to the trans guy, we dropped the pan and pulled the vb. everything seemed fine, nothing needed to be messed with. its also never really had fourth gear. i can coast in od and drop it to d and feel it engage 3rd and slow down the car, but any acceleration puts it in 3rd