Gravely ZTHD 60 was fine. I changed the blades by lifting the front with my hoist just enough to get in there, and when I finished it was very slow on the right side in fwd and rev. I had to slow the L side down maybe 20-25% to go straight. I did an air purge but no change. Belt is newish. Exam of the linkages shows nothing bent or different from L to R. I did use the mower to drag a tarp with some dirt before this, maybe 100 lbs or 200? Would that hurt these? It didn't strain or spin the tires. I have been mowing with it and there is no leaks or noises, levels stay 1/4" in the two tanks as they should. Out of warranty. Any ideas? 155 hours, service done to hydros at 75 last year with oem filters and m1 syn 15-40 oil.
Hydrogear 3100 right side slow now
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So glad to hear that it could be the problem, I was going nuts. Raise it up and it's broke, wth? I wonder if filling up the two tanks just while you raise it might help. Not sure where the air could come from, worth a try. I'm going to do an oil change on that side, maybe the air is stuck in a weird place. They sure didn't do us any favors by putting the fill/vent cap 1/8" under the frame. On mine you can unscrew it and then you have almost zero clearance to remove it. I have to fill the overflow tanks and just wait for hours as it seeps into the trans and then be there when it overflows. Just stupid.
There's no fill plugs at all on the 3100's?
I had hydrogear ZT-2800's on my 2010 model year Cub zero turn. It had top mounted expansion tanks and side mounted fill plugs (on the inboard side of each) They drained by taking the little spin on filters off.
I agree with pulling the bypasses with the engine idled up a bit and keep pulling the lap bars forward and back.
I had hydrogear ZT-2800's on my 2010 model year Cub zero turn. It had top mounted expansion tanks and side mounted fill plugs (on the inboard side of each) They drained by taking the little spin on filters off.
I agree with pulling the bypasses with the engine idled up a bit and keep pulling the lap bars forward and back.
C/O oil and filter today, oil was like new. Correction: 15-50 M1. Did the air purge for 10 minutes, still the same. Fluke temp gun temps identical at 107-108. I noticed that the bypasses made little difference in trying to push the mower, (really) hard to roll either way. I don't think the brakes are dragging as when it's off the ground the motors turn the wheels equally whether the parking brake is on or off, and I verified free movement of the brake levers at the trans. We have an identical unit at our RC flying club (I also service) that is punished mowing 5 acres of tall grass weekly closing in on 500 hours still on the original belts that goes fast enough to blow your hat off, as mine used to, so I know mine is sick somehow. Mine goes fast enough to mow, I just wonder what happened to it.
It should freewheel completely with the bypasses pulled. Could there be something preventing full bypass? Debris or something bent or out of alignment?
Went out to check that this am, the Bypass mechanisms are hooked up and moving fine on both sides. I tried to drive it a little in BP and maybe break it free internally? Drove normally. THEN turned motor off, put BP in mow, and R side wheel wouldn't move at all- Uh oh. Put back in BP, now it's working, back in mow,, still working OK Phew! L side still not able to freewheel. Speeds are still the same L normal, R slowish. Here is a good vid of a rebuild, there is a small doodad that the BP moves internally, can't imagine what could happen there. Sheesh, I think I'll quit while I'm ahead.
is the BP piece.
is the BP piece.
The units should not drive at all in BP mode. If it is, it's not bypassing properly.
Given the hours on them, it's gotta be something simple. I would expect a lot more out of those 3100 drives. The 3100s have been used on commercial grade zero turns for years now.
They used to be, now they are not. Just off an inch at the most. Nothing external looks bent or out of adjustment. I've taken the wheels off and studied all the linkages on both sides, nothing stands out. Wheels do not rotate when in neutral (when running and parking brake is on). I've backed off the allen screws that you use to adjust the speed for straight-line travel to get full action on both sides. The speed difference is pretty dramatic. Second pic is full reverse.
I spoke with the Hydrogear Techs by phone today. They seem to want to help. I told him about the slower right side and also about the Bypasses not letting the trans freewheel and he seemed pretty surprised by that (bypasses). Said the only way it would move while in B/P is if the linkages to the rod that goes to the internals was bent or not moving the full range. I disconnected the linkage from the rod and it moves freely from stop to stop, both sides the same. I took the wheels off and started the mower and watched and listened as I moved the bypass in and out while in full fwd. Nothing, no changes. Then I mowed for 30 minutes with both sides in BP. Out of ideas again...........
