Both the pump & telescope cyl in this trk have worked perfectly since day one.. even after virtually sitting the 1st six yrs, never a problem with air bubbles or loss of pressure. I rarely go up on the 3rd stage & the box is small enough that the hoist is rarely stressed much.
I had dual pumps with dual wdc telescopes on my end dump trl.. I had trouble with one of the telescopes, 2nd joint kept popping apart.. then I went to the Leimbach 5 stage telescope with dual pumps, the Leimbach usually hung up coming down, sticking on the last widest stage. Going up with a heaped box of dirt, no hesitation.
Overall, the four wdc pumps I have been using for many yrs have never failed me with loss of pressure or leaking fluid. That's the one good item I can speak highly of from wdc.