Gday I am a mowing contractor in Australia and I have bought the 2nd hand mower from hell. I have already had to replace a cutter deck gearbox and the latest is that the 30hour old cutter deck gearbox (its a driveshaft from motor to cutter deck and this gearbox transfers driveshaft power to the belts on the cutter deck) has a leak from the seal. The reason for this leak is that even though there is a grass shield on the seal grass has found its way past and into the seal which has caused the leak. Question: How long is too long for a ZTR to cut, my deck can be raised to about 6 ½ inches for slashing. Scag are saying that the problem is that long cut grass is wrapped around the driveshaft if I reverse back over cut grass i.e. the windrow. This grass then forces its way back into the seal and ruptures it. They say that a ZTR being Zero turn should not be run backwards whilst cutting but turned around and cut in forward mode. A fair comment but nothing is said in the manual about this. So it seems that I have to pay for a new gearbox ($800 + labour)and now new seals ($?? + labour) before I learn this lesson. How long is too long?? Is this seal problem a known problem??