Changing oil in Hydro-Gear ZT-2800/3100/3400

[@DexterFarmer-bo8yr]

The direction on hydro gear manual says to disengage the transaxle and move the controls forward and backwards 6 times to purge the air out of the system when I serviced mine only one would disengage. I noticed you didn’t do either one. Are you sure all the air was purged and how do I know if mine is purged out of the side I couldn’t disengage.

[@YetiSmasherOhnO]

Invest in thin-profile wrenches for easy access to the vent-bolts. I couldn't fill my transaxles at all through the reservoir without cracking those vents. edit: my Exmark Radius manual had me unlock and lock the hydrostatic bypasses (the knobs you release to be able to push your mower by hand) over and over during bleeding. So I was hopping on and off, wheels not spinning while unlocked and spinning while locked. I did this probably 7-10 times before fluid levels stabilized.

[@JoesGarageProductionsLLC]

I changed the hyrdro fluid again last week and had no trouble cracking those bolts with a normal wrench.

[@BrokenPortriats]

Good video...Thank you.....Hydro-Gear said oil filter cover bolts on ZT trans go down @ 65 inch pounds (5.5 foot pounds) and vent plug @100-120 inch pounds ( 9 foot pounds). Hydro-Gear did not warn of their little steel bolts, holding the oil filter cover on, wanting to seize in the aluminum housing. My friend found that out the hard way on his. That made for a very-very long day. Also Hydro-Gear said trans oil filter should be tightened to 80 inch pounds (6.6 foot pounds) or 1/2 to 3/4 turn after rubber seal contacts face of sealing surface (same as car engine spin-on filters). I work on cars. Mower transmissions seem similar to hydraulic car power steering systems in some ways. I never start the car engine after emptying and refilling the oil in a power steering system as thousands of little air bubbles will quickly be formed by the pump and may cause damage to pressure pump vanes (Hydro-Gear doesn't use vane style pumps as far as I know). Also may take days before all the air bubbles go away while the pump whines away loudly. I first turn the steering wheel lock-to-lock at least 10 turns to get most of air out. Question: What would happen if, before starting mower engine, the drive tires were each turned by hand a few turns in each direction to begin clearing most of the air from system? Would the direction handles need to be moved forward and back at the same time? Would the trans belt need to be removed? The trans has a lot of gear reduction in it so this may not be possible.

[@ajrollan5304]

Ty for the video, great pointers

[@keithphillips1234]

Did a very good job man!! Thank you

[@brontoab1]

Hydrogear did not cut the threads on my right side transmission oil filter connection. Hopefully running a die over them will clean them up enough to get an oil filter back on there. Absolutely unbelievable.

[@jaredrichards7094]

Dont remove the réservoir.. they have bleed bolts on the under inside top of the hydro... pause at 10:00 to see this bolt. Just above the belt. Once oil starts dripping out of there youre full. Way easier than taking off the reserviors.

[@CCPcoatingscom]

You flush the hydro system with ENGINE oil?

[@JoesGarageProductionsLLC]

Correct. Won't hurt anything.

[@blueshadow5617]

plastic guard for longevity probably it's the same way on an exmark radius series

[@TheYamahog12]

“We would jam in Joe’s garage…”

[@johnoler357]

Damn Dude, You need either a pit in the floor, or a hydraulic lift to work on that sort of stuff. Another 10 years and you are not going to want to be moving around that low to the ground. Just watching this is making my joints ache.

[@justinb7558]

My machine has no expansion tanks. What do I do different?

[@markmeister2444]

Justin, the only thing I can tell you is if you remember about those vent plugs on the side of the trans case that Joe talked about, take those out and fill until the oil just starts to drip out, and then replace the vent bolts.

[@justinb7558]

@@markmeister2444 Mark I guess then after the purge procedure I would have to pull the vent plugs again to make sure oil is still coming out of the vent hole to ensure it's full after the air is bled?

[@markmeister2444]

@@justinb7558 That would be my guess Justin. Probably wouldn't hurt to check it a couple times, these drives are expensive you can't be too careful. good luck.

[@justinb7558]

@@markmeister2444 thanks for the help buddy and good luck to you also

[@markmeister2444]

@@justinb7558 You're more than welcome Justin.

[@barybaryton2297]

how many oil for zt3400?

[@JoesGarageProductionsLLC]

That information can be found on page 9 of the Hydrogear service manual, located here: www.hydro-gear.com/wp-content/uploads/2023/03/BLN-0108_3400_3600_3800.pdf In summary, about 2.25 quarts for units w/o an internal expansion tank and 1.75 quarts for units w/ an internal expansion tank

[@barybaryton2297]

@@JoesGarageProductionsLLC many thanks....many regards

[@M70ACARRY]

Newer Hydro-Gear 2800's don't have external expansion tanks. They are internal now. Don't care too much about it.

[@JoesGarageProductionsLLC]

Funny you mention that. A neighbor just bought a new Scag Liberty Z with the 2800s and you are correct... No external expansion tank.

[@H60ace]

I think you probably tightened that filter down way too tight. It might give you fits when you change it again.

[@onewayt]

Pretty good video thanks but that ain’t a tractor

[@johndavis7112]

FOR ONLY 50 HOURS THAT OIL LOOKS NASTY ON THE FIRST HYDR UNIT

[@BrokenPortriats]

I noticed that as well. Changing the oil while it is nice and hot is a very good idea. Ex Mark says to wait until 100 hours before doing first trans oil change on new mowers !! Screw that ! My new mower only has 35 hours on it and I plan on changing both the engine and trans oil every year before I put it away.