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Attn: Powermax owners

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I may go to an auction with 3 AC 720's. How do you tell if the hydro is good? What is considered low hours? Are there any common problem you shold check for? All have 60 in. mowers, no other attachments listed. What can I expect them to go for? I also found a 4040 with 2500 hrs. for $1250. Is that good or bad? Any help is welcome, thank you, Jordan.

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These tractors have three speed ranges (set by a shift lever at lower left under the seat). First put the tractor in low (1st) speed range. At half throttle the tractor should jump pretty good when you operate the hydrostatic drive lever. You should hear a "whine" in the transmission if you operate the lever quickly. This is normal as there is a relief valve called the acceleration valve that limits "jerk" from operating the lever too quickly. Then, in second range and about half throttle, run at a normal mowing ground speed and operate one of the hydraulic lift levers. This should not affect the ground speed considerably. You will probably notice a slight affect on ground speed. This is because a small pump called the charge pump at the front of the hydro unit is used to both operate implements, and make up leakage in the main hydrostatic pumb/motor assembly. Wear in the hydro unit would mean more leakage and thus starve the charge pump when operating hydraulic lift. When in third range, you would most likely feel a noticeable lag in ground speed when operating the hydraulic lift lever. The hydrostatic pump & motor are working very hard and at a higher pressure to maintain a rapid ground speed. The high pressures create more leakage in the hydrostatic assembly, and thus the charge pump needs to put more oil into leakage makeup. If in third range you cannot quite get moving while operating the implement lever there is a lot of wear and a rebuild is probable. Try all three tractors and compare their responses. You'll know which has the better tranny. Powermax_Paul

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