Wheel horse 520h transmission issue

[Mattorze 2]

Hello, I recently added a 1990 wheel horse 520h to my collection. It runs very well but there's something wrong with the transmission. First off it's very slow in forwards so I'm assuming it just needs adjusting, however the longer I drive the tractor the slower it gets and eventually it just crawls along. I tried changing the fluid and filter (Mobil 1 10w-30 and Toro filter 79-5270) and changed the drive belt but it's no better. I'll be driving the tractor and when it goes down a hill it picks up speed but when it gets to the bottom it stops and then will start moving again, almost like it has to think about what to do! This thing has me stumped and I sure could use some help.

[lynnmor 7,354]

Under the seat is the cam atop the transmission.  The motion lever should push the cam all the way and the friction washer should be adjusted to keep the cam in place.  While you would need to be a contortionist to observe what is going on, do the best you can to establish the cam movement.  The tractor will pick up some speed down steep grades and there is some delay like you described.  The transmission is pretty stout, but a failing hydro is a possibility, just rule out the external controls as they are the most likely cause.

[Mattorze 2]

Lynnmor, I have looked at the linkage and everything moves freely and stays where I put it. The hydro lever does not move while driving and as I'm going down hill, or anyway for that matter, if I move the hydro lever down(decrease speed)  i feel it slowing down. I feel confident saying this is not linkage related. I will verify if the cam has excessive play or slop, maybe it has too much backlash?

[benji756 341]

try chaining it to something that won't move and see if it will spin the tires, this may help determine if the tranny is getting weak also how fast will it go in reverse?

[benji756 341]

also to

[squonk 41,367]

To me getting worse when it get's hot is a sign the hydro is failing. I would remove the seat pan and make sure all the cooling fins are clean. Lots of grass and grease usually end up there. If it's clean, I'd start looking for a new pump or complete trans setup

[Mattorze 2]

I cleaned most of it off yesterday. It was packed everywhere with dirt and grass from over the years. I was amazed how much dirt was on the ground when I finished blowing it off. I'll try to get it out today and chaining it to something.

[lynnmor 7,354]

1 hour ago, Mattorze said:

I cleaned most of it off yesterday. It was packed everywhere with dirt and grass from over the years. I was amazed how much dirt was on the ground when I finished blowing it off. I'll try to get it out today and chaining it to something.

 

 

A hydro will quickly overheat if packed with debris or the fan slipping.  Do the tree test, the pump might be toast from all that heat.

[Mattorze 2]

I just finished the test. I cut grass for a while trying to heat up the oil and then chained it to a tree. Once the transmission got under a load the pump began to whine loudly but it did manage to get a rear wheel to spin. Tried this twice on hard ground and it spun the wheel. It could be just me but it seems more responsive in reverse. I'll quickly put in in reverse and then back to neutral and it will skid the wheels on the ground and stop but if I do it in forwards it rolls for a little while and stops. Does this tractor have the two valves like a cub cadet? 

Edited May 6, 2018 by Mattorze

[Mattorze 2]

Quick update, so this afternoon I took the cover between the center console and fender off to check the control lever linkage. I found that someone unscrewed one rod 7 full turns. I screwed it back up to the nut and the tractor flies in forwards now but sluggish in reverse so I'm going to dial it in perfectly this weekend. I also found a lot more dirt so I'm gonna wash and get her to shine again. It seems just adjusting the linkage has somewhat resolved the issues I was experiencing. This being my first hydro wheel horse I have a few questions. First, should the tractor be hesitant moving forwards slowly but strong when moving fast? Second, should the tractor pick up speed going down hill moving forwards in half forwards speed setting? Third, could the pump be showing signs of failing even though it spun the tires when tied to a tree? This is my first Eaton hydro so I'm not sure what to look for or what a normal operation is. What I do now is my hydro cub cadets are very responsive at any speed and don't act like this transmission. So it just the nature of the beast or should I expect a rebuild in the short future? Thank you