Dale,
I have never dealt with a lift that lowers with hydraulic pressure so I am deficient in knowledge. My bed lowers passively with gravity but it will lower with the PTO turning or with the engine off, as long as I am putting the valve in the down position. Why don't you try lowering yours with the PTO disconnected and/or the engine off. If it lowers, then that is how you would do it to engage a blocking device, regardless of what type you have.
Kent
Last edited by Lightholder's Dad; 03/05/2021 11:43 PM.