I was out of town last year when a crew had a problem with a z. Had guys take it to the dealer to get fixed. They said drive axle broke and messed up the hydro on that side. They replaced both. It was toward the end of last year when we got it back and didn't use it for more than a couple days. Now, as was the case last year, that hydro takes several minutes to warm up and operate properly. I have never had problems when installing new hydro or changing fluids, I refill and run the hydros with no stress, machine jacked up off ground, and that works out air in system. The dealer is telling me it just needs to be run more to get the air out of the system. Could this be true, it's probably been run for 10 hours since the repair.