Hello to all the wise voices who make up the forum. I came across the forum by happen-stance while I was trying to find out what exactly was involved in changing the hydraulic fluid and filter on our Gravely Pro-Turn 160. The place that sold me the mower wants $191.00 for parts and $250.00 total to do the work. I was told by a friend that it could be tricky if you don't know what you're doing - and I've read the previous postings from a few years ago that explain the pros and cons of doing it yourself. I just looked at Gravely partstore.com and found the 2 filters for $16.04 each. $15.00 S/H makes it 47.00. 4-6 quarts of oil couldn't be 144.00, could they? J Thomas has the filters for $9.00 each. Sounds like somebody's makin' a killin' on their prices. I'm not a mechanic but I can read my Owner's Manual and I love to mow our 2 acre lot with a 1/3 pond on it. I'm mostly not sure about purging the system, etc., etc.