What is the best way to adjust the transmission on 518H?

[graywolf1939 24]

I have tried to adjust the hydrostatic transmission according to the manual without much luck. So, I tried adjusting the plate and the adjusting position which is under the seat. I cannot get enough FORWARD speed to cut grass. I have enough backup speed. No matter where I adjust the control plate position, I just cannot get the tractor to move faster in forward with control speed lever at max. This tractor has never had the hydraulic fluid changed since tractor was bought new in 1988. Some people have said it does not need changing, while other manufacturers such as Cub Cadet recommends changing the hydraulic fluid on a set schedule. Yes, the fluid level has been checked repeatedly and is always at full mark.

My questions are:

1. Should I change the hydraulic fluid?

2. Is there a better way to adjust the forward speed of the transmission?

3. Could there be another reason for the lack of success in adjusting the transmission such as worn parts? ( I don't see any wear on the plate adjustment under the seat.)

Thank you in advance for any help.

 

Dick

[kpinnc 12,357]

Domestic 518-H models use the 700 series Eaton, so the transmission "pump" is separate from the gearbox sump. Changing the oil on this model means changing the pump oil, and changing the gearbox separately as well. There should be a drain on the bottom of the pump. Be sure to clean it VERY clean before opening it. The smallest grit will destroy the pump.

 

The other point to consider is that the 700 series have about 1/3 of the torque that the 1100 series (with hydraulic lift) have. That, along with the fact that your pump has never been serviced may mean it has worn to the point that it is no longer servicable. Of course an oil change to find out won't hurt anything. 

 

The adjustment cam on top is for setting neutral, not setting forward/ reverse travel. The link that connects to it can be adjusted shorter to maximize forward travel, but the cam adjustment won't change forward speed without throwing neutral out. Also shortening the link will be a trade off. Any increase in forward will have an equal reduction in reverse. The only other possibility is that the entire linkage has slop in it due to wear. You might gain some travel by replacing any worn parts that allow play.

 

 

[Tuneup 1,433]

Yes, look to the linkage for wear. It's been a little while since they hammered on that in Indiana, right? My 516 was worn down there. Slop in the handle. Mine also didn't have enough backward speed, even with the linkage repaired and adjusted correctly to the plate. The new cam installed had to be relieved to get the backward speed desired. I always assumed this was some sort of safety feature. Your stating that backwards speed is OK suggests the setup is offset toward reverse.

[gwest_ca-(File Mod) 11,090]

What we have for the 518-H - 40 search results on 2 pages

https://www.wheelhorseforum.com/search/?q=518-h&quick=1&type=downloads_file

[graywolf1939 24]

Thank you all, I will follow all the excellent suggestions and see what I can correct. I was late getting reply because everything happens in threes, my computer was having trouble, so that I am working on, and our Cub Cadet  2005 model year , series 1000 lost its drive belt, and it is a royal PITA to change that belt, so then the car developed a rotational noise, so I need to check the brake pad clips. Am I having fun in 90 degrees outside with RH of 86% and dewpoint of 71F ? Hell yes. I will post my results as soon as I get anything completed.

[graywolf1939 24]

The manual calls for SAE 20 motor oil in the hydrostatic pump reservoir, and not filled to within 1 3/4" from the top when COLD. I had thought that the hydrostatic transmission would be using hydraulic oil, but that is obviously a misconception on my part. #20 plain old motor oil of good quality is what the manual calls for. It is interesting to note that the manual states that the hydrostatic oil should never need to be changed unless servicing due to leak or other repairs.

The transaxle per the manual calls for 10/30 motor oil, changed every 100 hours of use. I guess I am way overdue for that change.

[Gasaholic 226]

Those hydros could be fickle at adjustments, like others have pointed out, the adjustment plate (eccentric cam with a hex, and a bolt through it) - you turn the cam to adjust for neutral detent. Travel & speed are affected by the linkage rod length, as well as the bushings that hold the motion lever (Set parking brake and check for slop in the motion lever is what I usually did) and the ball joints at the ends of the rods were almost always the culprit when it came to the tractor slowing down from when it was new (Unless someone not as well informed tried to "fix" it by adjusting rod length or modifying the motion lever or trim plates)  Other than that it was wear (Heat would kill those Eatons, so it was important to clean out the gunk and grass build up in the cooling fins regularly - they rarely had failure issues until someone tried to change the oil or overloaded (again causing heat) or neglected the unit, so oil changes were somewhat rare - More problems when the pump was being used to power hydraulics (Again heavy use/overloading causing excess heat, plus changing out hydraulic hoses without paying attention to cleanliness, etc.)   

Myself, I much preferred the Sundstrand units which always got oil changed with transmission oil and filter - Much more oil so heat was less of a problem, although oil changes were really important as wear from transmission gears & bearings could build up grit that eventually wore grooves in the slipper plates (Hundreds of rebuilds spending a half hour or an hour polishing them on 600 grit wet or dry paper on float glass!) 

 

Our "cheapo" hydro test was to tie a chain around a stump and hook it into the rear hitch and see if we could make tires spin on dirt/grass - if they couldn't spin tires (when new, they'd spin even at very low speed), transmission needed a rebuild. 

[kpinnc 12,357]

1 hour ago, Gasaholic said:

Our "cheapo" hydro test was to tie a chain around a stump and hook it into the rear hitch and see if we could make tires spin on dirt/grass - if they couldn't spin tires (when new, they'd spin even at very low speed), transmission needed a rebuild. 

 

I don't know if putting any hydrostatic in that type bind is a good idea. If you have a hill in your yard, and the tractor will climb it without shuddering or needing the control lever maxxed to do it, your transmission is likely ok. 

 

Hydros whine under load. ALL of them. So long as it powers smoothly through a climb, it's good. 

 

Another note on the 700 series- never push or tow it. The 1100 series can be rolled, but the 700 has no relief internally so forcing it can cause permanent damage. 

Edited July 26, 2023 by kpinnc

[Gasaholic 226]

1 hour ago, kpinnc said:

 

I don't know if putting any hydrostatic in that type bind is a good idea. If you have a hill in your yard, and the tractor will climb it without shuddering or needing the control lever maxxed to do it, your transmission is likely ok. 

 

Hydros whine under load. ALL of them. So long as it powers smoothly through a climb, it's good. 

 

Another note on the 700 series- never push or tow it. The 1100 series can be rolled, but the 700 has no relief internally so forcing it can cause permanent damage. 

Yep - our test was only a few seconds , and generally was not an issue - if the hydro WAS gonna fail because of that load on it in a matter of 2 seconds, it was gonna fail on a hill as well. - Problem was for our shop location, we didn't HAVE a hill to test on.. so when customer brings in tractor to fix because it won't climb the hill. we had to have a way to actually test before AND after to verify the problem and the repair. Obviously it is not something we'd have done if the tires were sitting on concrete or other surface that wouldn't easily slip (grass, gravel, loose dirt was fine) and we did not have any load on top of the tractor (temporarily bypass seat switch for the test, tech NOT in the seat)...  It was far faster and actually more effective than hooking up pressure gauge set - pressure gauges would only test the state of the hydro system, our test tested the whole drive line (including finding sheared keys in axles and the like that hydro pressure test would never have found) 

 

Oh yeah, as for the 700 series, to tow it, we made an accessory carrier (re-purposed a low-slung dump cart) we could roll the back wheels up onto and then the accessory wheels would let us push/tow those. 

 

 

Edited July 26, 2023 by Gasaholic

[graywolf1939 24]

 Several years ago, while cutting grass on a very hot day, after about 2 hours, the engine quit. I lifted the hood and I saw smoke from the engine. What had happened was the air intake. Wheel Horse made great riding mowers, but they fell short in some areas of design in my opinion. One being the AIR INTAKE. It never should have been on the SIDE of the engine because leaves, dry grass etc clogs the protective screen, this causes the engine to overheat. All new riding mowers have air intakes on the TOP of the engines, well protected from any debris clogging the air intake. So, in my case, the coil was dead, and the electronic module was cooked due to excessive heat. I had to take half the tractor apart to make all the repairs, and $$$$ just because of poor design for air cooling on the side instead of TOP. Now, to get the tractor back to the garage from 300 feet away meant towing or pushing it back. Lifting the release handle to disengage the transmission did not work, I could not get the handle to stay up in locked position, So, we lifted the rear of the tractor up and towed in back with another tractor by the front wheels on the ground. 

 

Now for todays' issue, I could NOT find SAE 20 weight oil anywhere to replace the hydrostatic fluid as recommended by Wheel Horse manual. Everybody had 0-20W, or 5W-20, but NO just SAE 20W. So, I bought a quart of cub cadet transmission oil made for lawn tractors with hydrostatic transmissions, it is synthetic oil also which should be no problem. Seeing that the 518H was designed in 1985 or less for the 1988 market year, SAE 20W was what was the go-to at that time, this is 2023, 38 years later, many improvements have been made in transmission oils for hydrostatic transmissions.

 

[graywolf1939 24]

In doing some research both online and at dealers (NOT box stores) of riding lawn mowers, it seems that since 2017 the recommendation for Hydrostatic transmissions is 5W-50W synthetic oil. This was also the new recommendation for Wheel Horse model 518H also on every search online.

[graywolf1939 24]

Another question before I drain the hydrostatic transmission reservoir, I have read several threads here on this forum where one person said the drain plug was CW to remove the drain plug??? CW to remove was only used for propane/natural gas fittings, nothing else unless there was a change that I missed. Is the drain plug a CCW or CW to remove? The last thing I wish to do is strip the drain plug as one poor soul has done.

[graywolf1939 24]

Today while it was 92 degrees, it was a good day to work on the 518H in the shed in the shade. I took a few photos which I will include in this reply to my problem. First of all, the hydrostatic transmission (Eaton700) has a Left-hand thread, so it was necessary to turn the drain cap plastic head bolt CW to remove it. Why Eaton uses a CW loosen direction is beyond logic reasoning. The fluid did not look too bad after 35 years, but there could have been tiny bits of metal from original manufacturing, no way to tell without filtering the residue drain. Next was the transaxle drain, it had never been changed in 35 years either. Again, it did not look too bad at all, certainly not like my car oil changes after just 10,000 miles and 12 months. The 3rd action was to align the neutral on the plate and I had to shorten the control rod a bit, it also had never been adjusted from original setting. Then a rip-roaring thunderstorm hit with driving rain so final test will be tomorrow unless we get another expected TS.

The photos will show the condition of the plate, the location of the plate after adjustment to neutral and at high-speed position of the control rod. Another photo shows the location of the transmission drain screw removed. Comments welcome.

 

 

[Tuneup 1,433]

I really have to get on this list more often. Up early on a Saturday so . . . hoping you see this.

 

I'll give you my 516 experience. When going to buy it, she climbed a steep yard with no issue. Some added pressure on the speed rod was needed. Figured - old - not unusual. Got it home and used it for a year. My back yard is steep and I mowed it then up and backing down. In the heat of a Georgia summer, with the up and down being done about 20 times, the reservoir began to smoke. OK, in the garage. Drained it. I'd read about this trans being best with a full synthetic 15W-50 - this by a repair facility that specializes in it. She's been super ever since that Mobil 1 change. You have to fill it without the reservoir and hand spin it in both directions to purge the air but that's easy. Oh, I don't up and down mow that lawn anymore - ride across leaning hard on the high side. Tractor still stable, and with fluid filled tires. Trans has been great. Oh, you can push it short distances if you throw it full forward, though it does resist and, more when cold. I like the linkage tension on the light side so have to mow with hand on the speed control - yard very uneven.

[graywolf1939 24]

Thank you for your reply Tuneup. Before I add my reply and experience with my problem, let me add my prayers and thoughts for your 7 neighbors they were killed today in that mud slide that destroyed the resort in the mountains, 30 more missing and feared dead.

My 518 is one tired beast. Now I have it running OK again, what I did to adjust the transmission is as follows: I adjusted the plate while in neutral so that the top edge of the large washer was just touching the top opening of the slot. I also made an adjustment to the linkage shift rod about 2 turns shorter. I then changed the transmission oil to synthetic 10W-30. If our summers get much warmer for longer periods of time than in the past 40 years, I will change to 15W-50. When it is in the 90's and cutting 2 acres of lawn, some hilly areas, the oil after 30 minutes will be very thin and very hot. In Massachusetts (Central hills), we typically are in the 70-80's in summer, so 10W-30 has been the "go-to" oil. I am buying a new lawn tractor soon, it would have been another Wheel Horse, but as we know they are OOB. Anyone interested in purchasing a running H518 with commercial grade 48" mower deck?

[Handy Don 12,431]

19 hours ago, graywolf1939 said:

My 518 is one tired beast. Now I have it running OK again

The second WH I owned was a 400 hour 518-H. Unbeknownst to me was that the way the PO loaded and unloaded it from his truck had severely worn the hydro internally and it began to fail whenever it got warm. In the end, I transferred the good engine and some other parts to a 520-H roller and am very pleased.

 

IMHO, the P218 engine has most of the benefits of a P220 but with its less aggressive cam action it isn’t as prone to valve seat issues. (Keeping up with good cleaning, maintaining good cooling airflow, and following the regular maintenance are still critical, of course.)

 

It is pretty normal for the hydro to get up to 125 or 130º F. You can check this with a handheld infrared thermometer.

 

Assuming you are being meticulous with keeping the hydro cooling fins clean and the fan is in good shape, it sounds like your use case might be right at the edge of the capabilities of that hydro. I can recommend starting to shop for a 520-H with a bad engine!