1977 Johnson Stinger power trim wont go down

[Broughman52]

77 Johnson stinger 75hp power trim works fine going up but will not lower the engine back down. Motor runs when I try to lower moves about half inch and stays. Manual release valve when I take it out some fluid comes out motor stays up no movement. Both rams are stuck all they way extended as well. I removes the release valve and shuttle valve tries to hit the ball valve inside with no luck. Loosening the line on the bottom of the cylinder is the only way I can get the motor to come down what else can I try.