Started having problems at end of last summer. Ferris 2000 would not go.... checked the hydro fluid, and it tank was all but empty. Filled her up with regular hydro oil, and finished cutting. Yep, I know now you are suppose to use a regular syn motor oil. Dumb me. Fast forward to this year, got the zt out and same thing. Oil all over the inside of the rear tires..... So I replace filters, new oil, and back running smooth after a good warmup and just going back and forward. Stopped, checked fluid, and 1/2 tank gone...... fluid was steady dripping out of the rear fittings on both sides right inside by the rear tires and at the fittings. Everything feels smooth, and no noises, but it is spewing oil out in a steady stream on both sides. Fans are working, and like i said it seems fine to drive. So, did I kill the pump and drives?? It acts like it's not circulating the oil properly, and looking in the tank which is now 1/2 full its all bubbly and foamy looking. it seems like the fluid is being forced out of the fittings by the rear tires. I did not cut with it, just ran it back in forth in the backyard for like 2 minutes. Air lock?? This is going to cost me dearly I'm sure.