430 hydro surging

Hey guys, I had a 430 given to me that was a tornado survivor. I spent a little time fixing this and that on it this winter and have been using it to do the trimming and mow the ditches at my 2.5 acre rental property. It is a 1400 hour tractor and seems to run great! In low range the hydro seems to surge at mowing speed. If I put the hydro all the way forward it runs great, it also works great in high range. Any thoughts?

Junkman


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