418-A Tansmission/Pump Problem

[mattd860 161]

Next week I am picking up a 418-A with 540hrs on the clock. First thing I did was verify the hour meter works and it does. However, there is one major problem - the tractor only travels in reverse. When I push the hydro lever forward the tractor slightly skips and hops forwards but that's it. It will take 5 minutes for the tractor to travel 20ft forwards. But like I said, it travels perfectly in reverse.

Now I have a spare 520-H pump & transmission that I can swap out but I'm curious to know what may be the issue just in case I decide to fix it. Do you all think it is it the pump or the transmission that's causing this problem? I know the 'A' series has the weaker hydro pump but since the tractor can go in reverse without problem, I'm leaning towards a bad transmission (gear box).

Any thoughts?

[dcrage 621]

Ahhhh..... -- The 418-A I've been looking at has an Eaton 1100 in it -- Has the transmission filter and hydrolic lift, all that kind of stuff -- According to the Toro web site 418-A was only made in 1987 and has an Eaton 1100-032; I'm looking at the printout right now -- (This is one of those "Wheel Horse exceptions to the rule"; in this case the rule that '-A' means Eaton 700)

I know nothing about hydrostatic transmissions, but from what I have read here (RS), that would be a direct transmission swap

[mattd860 161]

Ahhhh..... -- The 418-A I've been looking at has an Eaton 1100 in it -- Has the transmission filter and hydrolic lift, all that kind of stuff -- According to the Toro web site 418-A was only made in 1987 and has an Eaton 1100-032; I'm looking at the printout right now -- (This is one of those "Wheel Horse exceptions to the rule"; in this case the rule that '-A' means Eaton 700)

I know nothing about hydrostatic transmissions, but from what I have read here (RS), that would be a direct transmission swap

Thanks. I know it's a direct swap but I was just trying to figure out why it travels in reverse, but not forward. Are you sure it has the Eaton 11 and not the 7? I thought all hydros (even the 520s) had the Eaton 7 prior to 1990.

[dcrage 621]

Matt

I have a printout from Toro that I was quoting in my previous message -- It says Eaton 1100 -- I haven't looked at the #s on the transmission of the tractor I was looking at -- I do know that the owner has a repair/part manual with it and it said Eaton 1100

[rexman72 210]

Matt i have the 417A with the eaton 1100.when i first got mine it went about 6mph in reverse and 1 mile an hour forward.What i did was change the filter and oil first.then i bought a cam plate for it and adjusted the rod from the motion lever to the cam plate.Its works great now.Hope this helps.

Next week I am picking up a 418-A with 540hrs on the clock. First thing I did was verify the hour meter works and it does. However, there is one major problem - the tractor only travels in reverse. When I push the hydro lever forward the tractor slightly skips and hops forwards but that's it. It will take 5 minutes for the tractor to travel 20ft forwards. But like I said, it travels perfectly in reverse.

Now I have a spare 520-H pump & transmission that I can swap out but I'm curious to know what may be the issue just in case I decide to fix it. Do you all think it is it the pump or the transmission that's causing this problem? I know the 'A' series has the weaker hydro pump but since the tractor can go in reverse without problem, I'm leaning towards a bad transmission (gear box).

Any thoughts?

[wheeledhorseman 573]

Good luck with this one. I'm still 'on the case' with my tractor which has the same symptoms in reverse (literally).

It's a D-200 with Sundstrand hydro but the principals are, I believe, the same.

Mine has plenty of pressure from the pump as the lifts work fine and it goes forward fine.

In reverse it will just about crawl on a down hill slope.

I discounted an oil change as it's clean and the filter as if blocked I would expect problems with all functions.

You may get lucky with the cam plate but as far as I could tell visually it was working fine on mine.

To be certain I removed the cam plate assembly and operated the shaft into the pump by hand.

The control plate limits how much speed can be achieved in reverse but even moving the pump shaft into full on reverse, which is not normally possible, there was little if any difference.

So when trying to reverse, pressure was being lost i.e. being bled back to the return circuit without passing through the motor.

There are, as far as I could make out from the diagrams in manuals, three places where this can happen.

So I removed the forward and reverse acceleration valves from the hydro motor and discovered that the spring that sits between the two spindles was broken into several pieces. Woo-hoo! Replaced the spring but still no reverse. More than one fault to deal with then.

I have one of the Ds fitted with additional relief valves which I understand act as dampers. They're connected to the motor via hydraulic hoses. If the reverse one is stuck open (another broken spring maybe) then it would explain the problem. I'm about to remove the hoses to these and blank off the ports on the motor to eliminate them from the equation. If it turns out to be these then I'll just leave them off. Wheelhorse dropped them from later production so I doubt you have these anyway.

If it's not the relief / damper valves then my last port of call is the reverse check valve in the pump unit. If the spring has broken or the ball bearing that acts as the valve isn't seating correctly then that's where I must be losing pressure.

Goes without saying that cleanliness is impotant when taking hydraulic things to bits and I had my tractor with the rear wheels off the ground when investigating motion without the cam plate assembly in place.

Hope this may be of some use. I did put up a post about my problem but few seem prepared to be drawn out in to the open on hydro issues.

Andy

[kpinnc 10,822]

It's a D-200 with Sundstrand hydro but the principals are, I believe, the same.

Yes and no. The basic concept of how they work is similar, but the way the pumps accomplish this is completely different. The Eaton pumps are far simpler because they are a ball-piston design. A fixed rotor, and a driving and driven side. Directional control is accomplished literally by squeezing the piston's travel one way or the other in the race. The Sundstrand, just as you've pointed out- has several ports and valves that operate inside the pump. The Sundstrand is more complicated, but is also serviceable by all of us who aren't the best in a repair environment, so to speak. If you can get the parts, you can fix the pump. Personally, I like the Sundstrands better. When an Eaton is done- that's all it is, DONE. It becomes a paperweight.

And exactly as you said Andy, when you open one of these (or any connecting lines) up- CLEAN is the rule. I mean surgery-level clean. One tiny contaminant, and it's all over.

I would change the oil, and install a new filter just for the heck of it. It sounds like the pump is starving itself for oil. I had one do the same thing, and it was because of a leaky axle seal. When I would park it, the oil would drain out on the ground. When I would comeback later, it just looked like a tiny drop was all that leaked, but it poured out while using it, which is why I didn't catch it at first.

To answer your original question Matt- Yes, the pumps are 100% interchangeable if it comes to that.

Good luck!

[mattd860 161]

I picked up the tractor today and changed the transmission oil and filter but it had no affect. The tractor still travels normally in reverse but will not go forward at all. When I move the lever forward I can hear a clicking/grinding sound coming from the rear end. It almost sounds like its coming from the gear box, not the pump but I'm not 100% certain. The linkages are all working normally as well as the hydro cam assembly.

The hydro lift also works perfectly.

Any other advice before I swap it for a known working unit?

[mattd860 161]

No responses? Am I the only one in the world that has a bad gear box instead of a pump lol ????

[kpinnc 10,822]

Any other advice before I swap it for a known working unit?

I would say jack the rear of the tractor up so the wheels can spin freely, and verify your differential is good. Rotate one wheel and see that the opposite moves the opposite direction. Then I would disconnect the rod that links the DCL to the cam and move it by hand with the engine at idle. DO NOT PUT YOU HANDS IN ANY PLACE THAT COULD BE A PINCH POINT!!! The lever on the pump has a tendency to "feed back" when in a bind, so the potential is there to mash some fingers. Be careful!

You may want to remove the rear fender for this: Move the cam lever at the pump all the way forward. Your wheels (or axles, at least) should rotate forward as well (rather quickly, I might add), and if so you may simply have a link adjustment to perform. If the wheels don't move, and the pump whines very loud like it's loaded, then something in the case is in a bind. If nothing happens at all, you may have a bad pump.

Just my two cents. It should at least give you a starting point.

[mattd860 161]

Any other advice before I swap it for a known working unit?

I would say jack the rear of the tractor up so the wheels can spin freely, and verify your differential is good. Rotate one wheel and see that the opposite moves the opposite direction. Then I would disconnect the rod that links the DCL to the cam and move it by hand with the engine at idle. DO NOT PUT YOU HANDS IN ANY PLACE THAT COULD BE A PINCH POINT!!! The lever on the pump has a tendency to "feed back" when in a bind, so the potential is there to mash some fingers. Be careful!

You may want to remove the rear fender for this: Move the cam lever at the pump all the way forward. Your wheels (or axles, at least) should rotate forward as well (rather quickly, I might add), and if so you may simply have a link adjustment to perform. If the wheels don't move, and the pump whines very loud like it's loaded, then something in the case is in a bind. If nothing happens at all, you may have a bad pump.

Just my two cents. It should at least give you a starting point.

Thanks! When I jack up the wheels and turn one wheel by hand, the other one does go in the opposite direction. However, when I turn the tractor on and engage the hydro, I can actually grab both wheels by hand and stop them from spinning. They do spin forward when the rear end is lifted off the ground but like I said, I can stop them both by hand. When I do stop the wheels, I hear a grinding sound from the rear end. During all of this, the pump sounds very similar to my fully operable 520h.

[refracman 166]

I wouldn't think it would go reverse and not forward as only the pump determines which direction, there is no change in the drive gears and if they are damaged how could it go in one direction and not the other?

But, with how you are descibing your problem it does indeed sound like the drive gears are the culprit. At this point I would change out the complete assembly as they share the same oil, and disassemble it just to see whats up.