Hydro Gear ZT-3400 Replacement

TigerFanatic1 · Mar 25, 2025

Are there any cheaper transaxles that will work in the place of the Hydro Gear ZT-3400? I have a 10-year old Gravely Pro Turn 160 that the transaxle housing and cover busted near the rod that connects the left and right together. I recently acquired more yard to mow, so will likely upgrade to a new mower but considering fixing this one since it only has 375 hours.

stevem5215 · Mar 30, 2025

Maybe find a used one ?
What caused it to break ? I've not heard of anyone having issues with these transmissions for anything breaking let alone a case of one.

5030 · Mar 30, 2025

Neither have I and curious as to how you broke it in the first place... Hydro Gear offers replacement parts including cases fyi.

TigerFanatic1 · Mar 30, 2025

I noticed some drag/shuttering on the left side at the end of last summer while I was mowing my ditch bank. I got on level surface, checked the hydraulic oil, everything looked good, and didn't notice any more issues while mowing the flat yard. This year I changed the engine oil and drove it out in the yard and noticed the drag/shuttering again. I had 155 more hours for the hydraulic oil change but decided that I would just go ahead and change it. When I headed back to park it, the drag shuttering got really bad, so I started working forward and reverse, and all of a sudden heard a pop. I will get some pictures shortly because it looks like it broke where a rod connects the bottom rear of the two transaxles. Almost like it was in a bind there.

Tinhack · Mar 30, 2025

Typically, those units are mounted to allow independent movement--Like a suspension. If they're tied together, you probably allowed one to get loose causing the break. Is the rod you speak of tied to the direction levers or to the housing? There is no direct replacement for Hydro Gear units. The mounting system is rather unique. They pretty much own the market now since Eaton abandoned the lawn service area.

As mentioned, you can get individual parts for the Hydro Gear units. You will need the model number and serial number off the tag. Left and Right numbers are different so don't use the opposite side because it's easier to read.