one way that you can differentiate between the cyl's and valve is to install a small ball valve on the front hose of one of the tilt cyl's. (some times the bypass does not uccur at the end of the stroke) you dont have to buy a 3000 psi valve to do this as you are not going to dead head long enough to cause a rupture, so usually $20.00 buys a valve and fittings to fit right in line. install it, tilt (about half way) back and close the valve. oil has to transfer between the cyl's for the mast to drift. no drift = cyl's...drift = valve.