Recently my l5740 HST had a slight surge when moving forward and reverse. Changed the fluid and filters, while doing this I noticed the rubber hose at the suction side of the hydraulic pump was cracked, replaced this. Now the surging is even worse and when I release the pedal quick it tries to go in the opposite direction. The linkage all connected to the pedal seem free moving. Looking for any advice to hopefully locate the problem before I have to look inside