Hydro gear ZT 3100 transaxle problem identification and repair

[@Scoot7827]

Thank you for sharing! Great demo of your work on the pump. We have the 3100 as well. New at 50hrs I drained the oil, repl the filter. About every 100hrs I service it again. Blow off grass/debris after every mowing. After 330 hrs or so the left charge pump o ring developed a leak. Picked up a HG oem o ring. Didn't observe any scoring on the pump parts. Torqued the 12mm bolts 60in lbs then 110lbs. refilled w/ oil and will complete the purge process later today. Cheers!

[@gtinteractivedesign]

Update: there are over 200 hrs on the rebuild now. No Issues so far. Btw all the internal parts are available. Hydro-gear tech support is very good. On their website you can download the service manual. Also, if you call their tech support number they can provide you exact part numbers for anything that you might need based on your exact model number.

[@zorantamamovic7296]

Hvala puno na korisnim savjetima.

[@battalion151R]

I have a zt3100 on a Husqvarna. Mine runs fine for a while then gets "sticky", where it's hard to make precision movements. After that it will make the grinding noise and wont move. If I get off and pull the bypass, then do a purge, I can get back to mowing. Sometimes this will last for a while, other times it'll crap out again in a few minutes. But, I can repeat the procedure and go back to mowing. So, I'm thinking Im somehow sucking air into the system. The oil and filters were changed last summer. I have a new charge pump and cover, and have a seal and gasket set on the way. I do have a minor oil leak in this transaxle. Looks like up high somewhere. Maybe on the driveshaft seal. Any ideas would appreciated. I've never torn one of these apart before. The neighbor sold me this mower for $100.00 so I'm not out much I can't get it repaired. I actually got it to use while I'm putting another engine in my 2004 Everride Warrior. The POS Kamakazi engine doesn't have an upper bearing oil gallery. Kawasaki knew about these engines but never recalled them. The upper bearing wallows out due to no lubrication. The seal gets destroyed and it slathers oil all over the drive belt. Then it eats belts every 2-3 mowings. I had an older, but dependable Kohler 23 hp. that I'm re-engineering into the Everride. I just have to figure out the new idler setup.

[@CoalMiner379]

I just ordered a new charge pump kit and service kit for my badboy zt elite right side drive transaxle it's so weak that it won't move under normal load unless you start moving the mower with the left side first. Did the charge pump help with your problem? I'm going to do another full service on it tomorrow with another new filter and put the new charge pump on it and see if it helps my problem before trying to buy a used transaxle or have to buy a new one lol figured I'd try the easiest thing first before spending around 800 dollars on a new transaxle you know lol, anyways any info ya got will certainly help me out

[@notoriousJPG]

Possibly an internal cylinder block is worn .

[@notoriousJPG]

Possibly check valve issue.

[@battalion151R]

@@notoriousJPG I got it fixed. After a total disassembly, the only thing that seemed to be bad were the two cylinders above the supply pump. During my journey through the transaxle, I took the center section out and polished very minor grooves out. That was the only thing that I did besides changing those two cylinders. The original ones were loose. I did have some fun with that little square bypass. It fell out and I had to look for a while to find out where it went.

[@bamf9285]

@@battalion151R Did you happen to get any water in your oil?

[@tobytester2674]

Great video! Did you happen to renew the lip seal (157) for the charge pump? The orientation for that seal isn't real clear in the service manual.

[@notoriousJPG]

Yes, alll seals and gaskets were replaced. The charge pump shaft actually has a couple options depending on the exact serial number. The master seal kit comes with those and you have to match up the one that it uses. When you get the master seal kit there will be ones left over because of these variances.

[@jremeee1599]

I just picked up a mower with hydro gears 3400. 420 hours. They are noisy. At idle they wine real loud. Not sure if the oil has ever been changed in them.

[@notoriousJPG]

Check oil level, then replace filters and fresh oil... Could be oil issue or air in the system.

[@jremeee1599]

I dropped it off at the Husqvarna dealer last week. I praying they are not toast. The fluid is full but dirty. It runs fine just really, really loud.

[@jremeee1599]

The noise sounds like it’s coming from up near the fans.

[@charleskutrufis9612]

Hi, Thank You for the video, very informative. Please say where you got the parts. If you did ,I missed it.

[@notoriousJPG]

Got the part numbers from hydrogear support and ordered parts from local dealer.

[@toddreed1640]

I tried rebuilding my zt3100 but did not know to check those pistons. So when it was still powerless I ordered a new at 3100. After installing it i noting it doesn’t exactly return to neutral but my biggest problem is there is no more power than the old one. Could it have something to do with the return to neutral or the way I installed it? Help.

[@notoriousJPG]

I'd double check a couple other items like you're pully, belt, tensioner, hub assembly, and neutral release lever. One of those could be slipping.. also be sure there's no air in the system, make sure you properly purge it after fluid changes. Good luck 🤞

[@jimlauth7587]

I would really like to find out how to reinstall the bypass pin. Mine fell out when I pulled the shaft out and I don't know what the orientation is when reinstalling it. Help!

[@notoriousJPG]

The case would have to be opened if it fell inside. .. then when assembling you need to use some grease to hold it in place. My video shows this process.

[@kr5289]

I'm in the process of taking apart the pump on my gravely mower when I took the charge pump cover off there is quite of bit of scaring around it on the case side what do you think could have caused it? the pump actually locked up while I was mowing. thanks

[@notoriousJPG]

There were probably some metal shavings floating around in the fluid. Also check the bearing and bushings for any play. There shouldn't be any movement in them.

[@kr5289]

@@notoriousJPG thanks

[@moviesynopsis001]

Do you know if the zt 3600 hydro is much better than the zt 3100 hydro, or is it mainly just marketing hype?

[@notoriousJPG]

Quality wise, mostly the same internal parts, but it's set up for more volume and a larger output.

[@stevepatino8907]

What was the number for the seal kit

[@JM-yx1lm]

All you have to do to check the cylinder block pistons is push one down all the way, plug the hole with thumb on other side and let go of rod, if it holds vaccume then its good. Also when you take the pistons out , there are little spacer things inside that can fall out so dont lose them.

[@transmitterguy478]

DID IT WORK?

[@notoriousJPG]

💯

[@michaelcongilio7484]

You could've gave a better instruction on the bypass rod and plate underneath that. An intricate detail. No mention.

[@ajrollan5304]

Amazing

[@notoriousJPG]

Thanks

[@swink49]

Ya well I did exactly what you did except it wasent 100 mph I couldn’t get that damn center peace out beat the hell out of it for an hr! So through the dam thing through my fucking window

[@notoriousJPG]

Ouch, sometimes ya just have to be lucky. 😉

[@peanutman6593]

Hydro gear transaxles need repair a lot because they’re junk. I will never buy another mower that features a Hydro gear time bomb transmission

[@rickcoleman8903]

90 percent or more mowers use these hydro gear units.

[@JamesSmith-p1x]

I agree the hydro gear transaxles are garbage. I’ve owned 2 exmarks with this set up and have had nothing but problems. Things leak like crazy. I’ve had to get units rebuilt and have had to replace a unit because of it. Had one hydro gear that started leaking before warranty was up and exmark replaced it. I have that same mower in the shop now getting a seal kit installed due to leaks. I had an older exmark lazer z I ran for years that had a split pump system with wheel motors. Never had a bit of a problem with that system. There are still zero turns made that use the spilt system. I just bought a scag tiger cat 2 with a similar setup to the old lazer z. I am done with the transaxle.

[@notoriousJPG]

Personally, I like the older style setup with separate wheel motors and pumps.

[@victorrippe5845]

I had a Encore Fuzion 34 that thing had EZT hydro transaxle and I put 4400hours on that mower and sold it running well cause I had it for 8 years it was an amazing mower how do you explain how long these hydros lasted me.