change hydro oil

[perimeterlandscaping@comc]

the air purging works over a 1 hr or so period so the air bubbles can work themselves up the line to the reservior. fill it to the required fill level and go mowing and carry some extra oil to top it off as the machine expels the air from the transmission.
changing the fluid is absolutely neccesary and critical to the performance of your transmissions. Ive dropped the oil and replaced and seen significant power increases from just changing the fluid. they are delicate expensive components to be looked after just as you would your engine

 

[RevB]

Hydro systems with resevoir tanks are just like a standard automatic transmission...you'll never drain them completely and there is no need to do so. And never flush them out, auto trans or hydro. If you have filters replace those first, new ones filled with fluid on installation. Then if you have a resevoir tank suck out as much as you can and refill to proper level. The goal is to replace any additive package (emulsifiers, zinc, or any other additive that the pumps require) that has been mixed with the new hydraulic fluid. That is to say, your new hydraulic oil will come with these items added, you don’t ”add” anything. No air to purge, no extensive disassembly. An inexpensive fluid sucker will get the job done or siphon pump, under $12 usually. Or just a hose and quick suck to start the siphon.

 

[Steve Smith]

Coincidently I am about to change the transmission oil in my ZTR also. They are Hydro Gear ZT2800 also. They do have filters. That is where you drain them. There is a vent plug at the top that you need to remove. It is a good idea to let them purge the air out slowly overnight. Run them slowly with the wheels off the ground. You will need to defeat the seat safety switch also. I am using after-market filters rather than the expensive brand name ones. I hope that is not a mistake. It calls for 20W-50 oil. Use synthetic if you can find it. Also remember the first oil change comes early at 50 to 100 hours. After that you can go to 500 hours.

 

[jcworks]

in ALL THE YEARS (DECADES!) I have serviced Hydrostatic Motor Drives I have NEVER used a torque wrench to install filters OR top filler plugs! EVER! You are talking about using a "cheater" bar to install filters and a plug and red flag warning bells going off in my mind! Read the service manual again please. Are you sure it is not INCH POUNDS? ...because it sounds like the use a cheater bar would be for some torque spec so high in the foot pound range that would require huge amounts of force. I find that very very very UNLIKELY. The last thing you want to do is make a mistake and go king kong with a cheater bar and bork up the aluminum threads. So please for the love of all things good and right, please refer to the service manual and not some online forum or youtube video dude telling you some ridiculous torque value requiring a cheater bar. It is most certainly NOT in the foot pound range and NO cheater bar would be necessary to tighten the filter and top bolts! Read the service manual ...

here is what I have ALWAYS done: hand tight...lightly coat the rubber seal on the filter with oil and hand tight, same thing with the top bolts. Hand tight. With the hand...no torque wrenches needed to do this.

there are basic things you will always want to do to prevent damage to the hydros when doing lube changes. I will list several tips that apply to all hydros I have ever serviced:

1. always lift the back wheels...on blocks for safety. I put the entire mower up off the ground, with the rear wheel where the hydros are located pitched down...gravity is your friend when you want to drain the lube...just makes the process easier this way. The key is safety. Because you are going to be starting the engine, sitting on it and running hydros after the oil change! . follow the service manual after the oil is changed...I LISTEN to the sound of the hydros during this air purge procedure...at low engine rpm...then as the sound changes, increasing engine rpm! You can hear the sound change. At first you might hear a slight squealing sound from the hydros....this squealing sound should go away as air is purged. Move the controls SLOWLY. Do not rack them back and forth like you are trying for gold in rowing. Make sure you move the steering bars back and forth and then one forward and one back motion...many many times. The service manual should show you the motion required. I do this for at least 2-5 minutes. THEN I turn engine OFF and let it sit for 10 minutes, grab a cold one, and then I look for leaks. A sheet of paper below the filters and filler plugs/bolts helps to find leaks. Fix any leaks...meaning simply hand tighten again.

2. The service manual should also show exactly how much oil. HOWEVER...AND THIS IS KEY. There will always be some oil that does not drain. So if you go by the service manual, which assumes the hydros are completely empty, then if you fill with the prescribed amount, then you will be overfilling..and that is not good and will damage the hydros. So What I do it measure how much oil drains out. It's a simple thing to do. Then THAT AMOUNT is how much I add. No more. No less. On some hydro systems, there is a reservoir and a min and max fill line. This is usually a COLD FILL LINE. Remember this when replacing hydro. Make sure the hydros are not hot when replacing oil to this line. Follow the service manual.

3. If you don't know what an equivalent hydro oil can be used, then use exactly what the service manual prescribes. (alot of people get confused about oil equivalents...so if this is confusing then just buy exactly what the service manual states). No need to become a rocket surgeon and use specialized oil additives. Just use the correct hydro oil per the service manual.

4. Clean the cooling fans. Just soap and water...since you are working in the area, its a good idea to clean then up..make sure there is nothing twisted around the cooling fan shafts and that the entire hydrodrive body surface is nice and clean...this helps remove debris and grime that can cause problems allowing them to run as cool as possible....I use simple soap and water and a small plastic brush... I do this after adding the hydro oil. This helps identify leaks during the purge test. If you have drained oil all over the hydro drive and machine will confuse you thinking you have a leak.

Cajun power you give a good explanation - as has some others on here. Oil: The manual says you can add 20w50 motor oil. I'll likely use whatever HydroGears sells, and filter. The manual says fill to the edge of the top port and no more. Torque wrench: I've already been told about that. I RULED THAT OUT. I went back to the manual and read it was INCH pounds; so just tighten with a standard open end wrench or socket wrench. I got that. Measuring oil: Thats a good idea measuring the amount I drain out. Thanks for your advice. By the way, I'm originally from La. Born in Monroe, later in life we moved to Hammond. Spent many days on the marsh at Leeville and Venice. I heard its all changed up there now.

 

[jcworks]

Coincidently I am about to change the transmission oil in my ZTR also. They are Hydro Gear ZT2800 also. They do have filters. That is where you drain them. There is a vent plug at the top that you need to remove. It is a good idea to let them purge the air out slowly overnight. Run them slowly with the wheels off the ground. You will need to defeat the seat safety switch also. I am using after-market filters rather than the expensive brand name ones. I hope that is not a mistake. It calls for 20W-50 oil. Use synthetic if you can find it. Also remember the first oil change comes early at 50 to 100 hours. After that you can go to 500 hours.

Steve Smith, I'm at 300 hours now. I never changed the oil before, and thats sort of what started this conversation. I had two Toro dealers tell me there was no need to change it till 500 hrs. I did what they said. BUT, I was talking to a HydroGears representative on the phone on another matter and he said, No....change the oil.

 

[jcworks]

Hydro systems with resevoir tanks are just like a standard automatic transmission...you'll never drain them completely and there is no need to do so. And never flush them out, auto trans or hydro. If you have filters replace those first, new ones filled with fluid on installation. Then if you have a resevoir tank suck out as much as you can and refill to proper level. The goal is to replace any additive package (emulsifiers, zinc, or any other additive that the pumps require) that has been mixed with the new hydraulic fluid. That is to say, your new hydraulic oil will come with these items added, you don’t ”add” anything. No air to purge, no extensive disassembly. An inexpensive fluid sucker will get the job done or siphon pump, under $12 usually. Or just a hose and quick suck to start the siphon.

RevB, I do have the reservoir tank on my machine. Its mounted to the frame of the machine. Good idea on the sucker. I'll look for one, though I'd think that would drain out when the filters are removed. "new ones filled with fluid": The trans filter mounts in sideways. It looks like the fluid would just spill out putting them back in full.

 

[jcworks]

Check that spec again. I'm pretty sure it said 120 INCH/lbs. No torque wrench needed. Just gently snug it up and check for leaks. If not, you're good, if you do have leaks, a little bit more until leak stops. Good luck

jdwalsh, yes I found that out. Went back and re-read the manual. Its inch pounds, no torque wrench needed. Thanks.

 

[jcworks]

I have a Scag Liberty Z 48" w/Hydro Gear ZT 2800's. I too called Hydro Gear who said to change the oil and filters @ 75 hrs. After riding on the mower for 10-15 minutes to get the oil warm, I pulled one filter and let it drain, then did the other. Re-filled the system using Amsoil Synthetic 20W50 and Hydro Gear filters. Went through the procedure of purging air from the system with rear wheels off the ground, but worked each side 15-20 times. In my case, the hardest part in doing this was finding a wrench to remove the filters, as there is not much room to swing that wrench. But alas, it all worked out. Make sure you have a pan/container under the filters as the oil rather gushes out when filters are removed.

BTBO, I have a nice big oil pan , 16 qt I think. I have a small oil filter "wrench" that I use on my 4 stroke outboard and the engine for my ZTR mower. It will probably fit, but I'll check that out before I start. I say its a filter wrench....its more like a cap that fits over the filter you can then loosen it with your hand. If I have to get another one surely auto parts stores should have that.

 

[LMPPLUS]

I have a 10 yr old Toro MX5060. 300 hrs. Two local dealers have told me there's no need to change the hydro oil till 500 hrs. I was talking to a rep at the Hyro Gear (I think thats the name of the Co.) about another issue and during the discussion he told me it should be changed. I'd like to hear from people who know on here that does not have any vested interest in the issue. My gut feeling is to have it changed, but I don't know. That brings up another thing -- I don't know if I feel comfortable draining and refilling the hydros. Is it something a homeowner like me can do?

Change the oil (20w50) synthetic oil and filters and ward off buying an expensive hydro pump/

 

[bertsmobile1]

99% of hydro failures happen because the oil and in particular the very fine particulates in the oil were paths between the slots in the valve plate or between the valve plate and the piston chest out of the system.
So to a big extent the more often you change the oil the better as every time you drop the oil the particulates in the oil you toss are removed.
The fact that you never remove 100% is irrevelent .

As for tension wrenches
People who do this eery day of the week end up with a proper feel for proper tightness
People who do this once every 5 years do not

Way back at a show a mod flogging tension wrenches had a stand with 5 bolts into blocks of steel
The public was invited to do them up to the specified tension & any one who got all 5 right won a tension wrench
In 3 days of classic car & motorcycle owners / repairers / restorers lining up to have a go they gave away 8
And no I was not one of the 8 despite trying at least a dozen times over the weekend because I really wanted one of their 6" torque wrenches .

Professions can usually wing it , advising rank ametures to wing it is a bad idea unless you want to replace a lot of broken off breathers .
I have just gotten back to work after a debilitating arthritus attack and funny enough when I check what I have done most are drastically under tightened .
Now I might get my "feel" back or I might not but until that day a quick check is a lot easier that a liability claim against me .