Thanks to LawnSite and You tube I solved the issues on my hydro-gear drive system I bet a lot of people fix their problems by reading forums but we don't get to see how it went and how they solved their problems. I have done the same thing. So this time I want to post how my problems got solved. I hope my experience helps some one out there. Machine- I bought a used Exmark Turf Tracer 48" WB. It worked fine at first butt... Symptoms- Over time oil started getting everywhere! It was on the outside of the pumps, On top of the frame, And underneath was plastered with gooey with oily grassy nastiness. Eventually the left pump (and the leakiest) would not power the left wheel in either direction when it was cold. It would kind of groan and surge as I worked the controls back and forth going in circles While my crew would look at me and ask each other, "what is wrong with him"!? The oil tank would overflow some times and the Oil was really bubbly. Eventually it would start working after it warmed up Diagnosis- I asked a local shop if the pumps could re sealed or rebuilt. They said if I did, it still wouldn't work and to just "runn'em till they fail" and buy a new pumps for $600 a piece! My friend has a lawn mowing business and he told me the same thing! It just bugged me, I couldn't believe they couldn't be repaired. so I started to search and found a couple you tube vids on how to rebuild them. Turns out they can be rebuilt for less than $200! Then Google lead me to posts on this site about other people fixing them. So I tore the pump apart that was giving my trouble and it actually looked really good inside. The valve plate showed some wear but but not bad at all. I couldn't see any obvious signs on what was causing the problems. So I continued to search threads here till I came across a thread that revealed the common Exmark problems with the brass crimps not being very tight and sucking air on some of the smaller hydraulic lines. Sure enough, mine were loose and sloppy! That explained the severe bubbles in my tank and even overflowing, 'till the bad connections warmed and sealed up. Turns out the pumps weren't even bad!! my oil didn't have glitter or shavings so that made sense. Solution- I removed the brass crimps on the two tees and installed hose clamps. The right pump had actually been replaced with a newer pump before so it was in fine shape. But I threw a re seal kit in it too while I was in there. The left pump was definitely leaking bad so Installed a new seal kit and a new valve plate while it was apart. I filled the pumps with oil as i put them back together, (Making sure indentation marks on charge pump caps were in the rite direction) filled the new oil filter, installed the pumps, filled the tank with oil, Jacked the back of the mower up, started it up, put it at 3/4 throttle and let it run in full forward. In about 10 minutes the air was out of the system and the wheels were running at full power and it drives great now! No air bubbles in oil and no leaks! Sorry this was long. Hope my story helps you get back on your sulky in no time!