I bought a 60" with bagger system model used this past spring to pickup fall leaves mostly. Use my 74" Walker mostly, but leaf time is coming. I have noticed after buying it the left hydro drive system is not real linear. Meaning it is more on/ off. I assume it is from always turning left more so around trees, etc. because of the deck layout and catcher on right. It is functional but long term I would like it to be better. The pump/ drive systems are separate for right/ left. Is it more likely I should try to replace the hydro pump or wheel motor for this symptom?