I bought a fastrack 3 years ago with the sealed IZT's. A year and a half later I took it back to the dealer to have a cracked weld repaired. It was during the State Fair and most of the staff was there on out on a service call. I did get the crack repaired and the younger person there looked it over- then pulled the IZT breather tubes and checked the oil level- which he said was low and then added some. I mentioned the units were sealed- and he indicated they were- but you could still check the level like the newer ones and gave me a guage to do this with. I recently checked the oil level again- now at 141 hours- and though the level was OK, the oil was not clear. It is hard to describe- it was not opaque and I couold see no particles in it. It was not "milk like" like I have seen with water in oil in an outboard tranny. It is more of a brown color- but if it is rust it must be very fine. The mower is out in the weather a lot, though I try and keep a tarp over it. I do not pressure wash it. I have read of Hustler recommending adding something to the oil on the IZT's. Is this where the color is coming from? The dealer is about 70 miles away so no easy way to run it over to them to look at.