You know, I had to adjust my draft control and three point linkage on an MX5100 last summer and when I had it incorrectly adjusted I heard a "hissing" type sound. It was more like a "straining" sound from the hydrauliics and it was under the seat by the draft control hydraulic levers. Just remembered that. After adjusting correctly, the sound went away.
Watch, after all this you'll probably find a snake under the seat...:laughing: