I bought a fire-damaged GX345 last summer and a butt-ugly 345 for parts. Very few of the parts that I needed swapped from the 345 to the GX345, so I decided to get the 345 going as well.The GX345 is stupid fast, and Tractor Data says they should both max out at 7mph. I know Tractor Data has some errors, but the 345 is considerably slower than the GX345. I do not believe this is the typical worn hydraulic motor issue, because it will still climb a fairly steep hill and maintain the same slowish speed that it does on flat ground. To be clear, the 345 goes plenty fast for cutting, it is just no where near as fast as the GX345. Both units have fresh fluids and filters. Any thoughts?