TG1860 Mower with PTO Problems

[TG1860]

I have TG1860 lawn tractor with 54" deck that I bought new about 23 years ago. It has a 20HP diesel engine with hydrostatic transmission. It now has almost 700 hours so I'm averaging ~ 30 hours per year mowing about 2.5 acres of yard. In 2021 the gearbox driving the PTO and other stuff ate the gears and was replaced with a "junkyard" unit by our local Kubota dealer.

Very recently the mower deck PTO hasn't wanted to engage when I pull the button. After a few tries it would engage and I'd continue mowing. Today it was really a problem and I'm thankful I completed mowing the yard. Afterwards I checked underneath the mower, expecting to see a wiring connection lose or something, and noticed a lot of oil slung around the PTO pulley area. I called my local dealer, talked with the service desk, and he says the engine must be leaking and has oil on the belt and the pulley is spinning on the belt instead of driving it.

I've not noticed any burnt oil smells to support the belt slipping and the belt really doesn't look oil contaminated. I did notice when I put away the mower the power steering was stiffer than it has been. So, I'm thinking the main heart of the drivetrain, the hydraulic pump / hydrostatic unit might have expelled some oil and is now not functioning properly. Is there any oil directly associated with the PTO pulley unit? Am I on the right track? Might oil have gotten inside the PTO gearbox and it's slipping?

I'll need to have this running again in another week and hope this isn't the end of life for this mower. Thank you in advance for any help you can provide. I've been a member for a few years but the need for help has been infrequent.

This is the conversation a couple years ago when the under-seat gearbox failed and was replaced.
Rattle under seat

 

[Highgrass23]

I have TG1860 lawn tractor with 54" deck that I bought new about 23 years ago. It has a 20HP diesel engine with hydrostatic transmission. It now has almost 700 hours so I'm averaging ~ 30 hours per year mowing about 2.5 acres of yard. In 2021 the gearbox driving the PTO and other stuff ate the gears and was replaced with a "junkyard" unit by our local Kubota dealer.

Very recently the mower deck PTO hasn't wanted to engage when I pull the button. After a few tries it would engage and I'd continue mowing. Today it was really a problem and I'm thankful I completed mowing the yard. Afterwards I checked underneath the mower, expecting to see a wiring connection lose or something, and noticed a lot of oil slung around the PTO pulley area. I called my local dealer, talked with the service desk, and he says the engine must be leaking and has oil on the belt and the pulley is spinning on the belt instead of driving it.

I've not noticed any burnt oil smells to support the belt slipping and the belt really doesn't look oil contaminated. I did notice when I put away the mower the power steering was stiffer than it has been. So, I'm thinking the main heart of the drivetrain, the hydraulic pump / hydrostatic unit might have expelled some oil and is now not functioning properly. Is there any oil directly associated with the PTO pulley unit? Am I on the right track? Might oil have gotten inside the PTO gearbox and it's slipping?

I'll need to have this running again in another week and hope this isn't the end of life for this mower. Thank you in advance for any help you can provide. I've been a member for a few years but the need for help has been infrequent.

This is the conversation a couple years ago when the under-seat gearbox failed and was replaced.
Rattle under seat

I just got a used one with 930 hours. The oil leak on mine was a broken/missing nylon vent hose fitting. Wasn’t the HST unit rather the PTO gear box vent.
I hope yours is something simple.

 

[ve9aa]

I've had the HST transmission spit oil everywhere when I accidently bumped the vent hose and then a bit later, it fell off, altogether spewing oil everywhere.

I've never had my mower PTO apart, but isn't it purely an electrically/magnetic like other ones (ie: not a real gear box). I could be off base with that, but that's what I've been led to believe but certainly stand to be corrected by those that know better.

You should hear the THUNK when the magnet(solenoid) pulls in and locks (oily belt or no oily belt). If you don't, it's most likely an electrical issue primarily, exacerbated by oil on the belt(s) causing you additional grief.

I've tore into my 1860 a bit here and there over the last 17+ years, but never been near the PTO so "grain of salt" and all that.

Good luck

 

[TG1860]

It seems the PTO is probably electromagnetic activated, and I didn't hear any thunk when it was activated with no results. It was like it was not receiving the signal to activate, so it could be the pull button. But the excess oil in the PTO area is suspect. I'll pull off the seat and body early in the week to take a hard look at everything. Hope it's just a hose off and oil spewed and something I can quickly fix.
The replacement PTO units are $400 when you factor in sales tax and shipping costs. I'll spend it if I need to, but only if I am sure it'll rectify the problem.

 

[ve9aa]

It seems the PTO is probably electromagnetic activated, and I didn't hear any thunk when it was activated with no results. It was like it was not receiving the signal to activate, so it could be the pull button. But the excess oil in the PTO area is suspect. I'll pull off the seat and body early in the week to take a hard look at everything. Hope it's just a hose off and oil spewed and something I can quickly fix.
The replacement PTO units are $400 when you factor in sales tax and shipping costs. I'll spend it if I need to, but only if I am sure it'll rectify the problem.

If it were me, I'd advise you to get familiar with a multimeter (if you aren't already) and start Ohmming out wires, checking for voltages, etc before firing the parts $400 cannon.

Odds are it's an intermittent switch or broken wire rather than the solenoid@ the PTO itself...though I am sure all that oil is certainly concerning ;-)

 

[TG1860]

I own a Fluke multimeter but admit I am no expert with it. I'll need a wiring diagram to facilitate the necessary checking. I've considered the fault may be in the pull/push button switch and its replacement cost is much more palatable at ~$25. It seems to have 8 wires connected to it and if I can figure out which is which I can utilize the Fluke to test.

I might find the splashed oil and the PTO fault are unrelated, but odds are they are related.

Yesterday I finished my last project in the garage, replaced the lower radiator hose on a GMC truck, and thought I was finished out there. Now this pops up and I need to give it focus as I race against the growing grass.

 

[North Idaho Wolfman]

I've considered the fault may be in the pull/push button switch

What your explaining, the switch is the most likely cause!

 

[TG1860]

Today I rinsed off the mower before moving it into the shop to begin work. When I removed the RH deck belt-guard I found what looks like a vent hose attached to a broken off fitting. That's probably the reason for the oil splashed around. Now I'm concerned my washing off the dust and rinsing underneath I may have introduced water into the HST gearbox.

I should be doing some disassembly early in the week.
Here she is after being washed off.

 

[lmichael]

I don't think that came from the gear box. Maybe the breather from the engine?

 

[TG1860]

Hmmm. I'll check the breather for a missing vent tube.

 

[North Idaho Wolfman]

If anything it's a radiator / coolant fitting?

 

[TG1860]

The vent hose is broken from on top of the gearbox located between the engine and the HST. The PTO is attached underneath this gearbox and is drenched in the oil that has splashed out. Tomorrow morning I should have this gearbox pulled from underneath.
Other than replacing the vent hose and topping off the oil I’m wondering if I can clean the oil out of the PTO. It seems to be an electric activated clutch, maybe some brake cleaner will cleanse it.

 

[Highgrass23]

Ex

The vent hose is broken from on top of the gearbox located between the engine and the HST. The PTO is attached underneath this gearbox and is drenched in the oil that has splashed out. Tomorrow morning I should have this gearbox pulled from underneath.
Other than replacing the vent hose and topping off the oil I’m wondering if I can clean the oil out of the PTO. It seems to be an electric activated clutch, maybe some brake cleaner will cleanse it.

View attachment 106420

Exactly as mine was.

 

[TG1860]

Who knows what kind of oil the gearbox requires? Might be a good idea to drain it and refill with fresh.

 

[lmichael]

I put in a little heavier synthetic in mine last summer. IIRC 85W-140 I think it's from Lucas

 

[Highgrass23]

Ex

Exactly as mine was.

I don't see the vent hose cap vent. Make sure to have one. Should be available at just about any auto parts store. Chevy rear differential vent. turbo 350 transmission vent. Lots of options.

 

[TG1860]

This morning I removed the gearbox with PTO and they were a mess. I scraped off the excess oil soaked crud, then brushed with diesel fuel, then rinsed with water. I still have to clean up the underside of the mower.

I was about to go to our local Kubota dealer across town to get oil, a vent tube fitting, a whatever filter to go on top of the vent tube hose and ask questions about cleaning up/out the PTO.

So, I called them first, and I get no answer. Their voicemail greeting says nothing about being closed today and tomorrow but no one will answer. So now I'm stuck here and cannot proceed until Wednesday at the earliest.

However, If I can establish what specific oil to use and maybe get the fitting at the local auto parts store, I might be able to get it back together. I do have a used vent tube fitting but it's 20+ years old and probably brittle like the other one was. If I had access to swap it later I might run with it for now, but access is very limited.

What oil for this gearbox? lmichael suggests "85W-140 I think it's from Lucas"

Can I soak the PTO in some kerosene, drain and blow it out, and then squirt a bunch of brake cleaner inside to clean the clutch contact plates? It doesn't seem to be made to be disassembled.

Can I test the PTO by connecting it directly to 12V power? Shouldn't I hear it click or something when under power?

One thing to note is when I drained the oil from the gearbox it looked milky, like maybe some water was whipped up in it. I think I'll rinse it out with some 0-20, then drain it well before I fill it with whatever oil it needs.

Is there an online Kubota service dealer that might be able to ship today if I place an order?

I'm posting some pictures because this may someday help someone else who is experiencing the same concerns.

 

[ve9aa]

On the PTO, I wouldn't put Kerosene or diesel in there........just brake cleaner.
You don't want any kind of lubrication inside of it (more than you already have-- )

Yes, put 12v on that thing and it should solidly pull in and snap. (watch your fingers)
If it does, then your issue is likely in the switch (easy to test on the bench with an Ohmmeter) or a broken wire (also, Ohmmeter). Not too much to it ! It's an off/on thing (magnetic). It'll either work or not.

On the other questions....sorry, I just know feel I know the answers well enough to advise.

 

[TG1860]

I understand your aversion to using kero or diesel to clean the PTO as both of those have lubrication properties. Gasoline would be a better cleaner but it's flash point makes it dangerous to use in this fashion. I'll use the brake cleaner. I used to use something called ElectroClean to clean electrical circuits but not sure if I can get any. Wonder how it differs from brake cleaner.

I'll try the 12v direct to the PTO after cleaning. I'll bet it'll work, but hope it isn't polarized and I connect it backwards. I'll also believe the failure I was experiencing was oil on the discs allowed it to spin instead of gripping to drive the mower deck. With the mower engine running it would drown out most noises.

The push button switch has about 8 wires going to it. Probably the seat switch and other safeties routed through it. I'm unsure which leads to check to ensure proper functioning. But maybe I'll figure this out as the project progresses.

 

[Russell King]

Look at the wires on the PTO for color. Then on the tractor harness connector verify the wire color stay the same and then look for that wire color on the switch and then you should know what wires to verify get voltage. I think there are only two in the picture of the PTO.

You might be able to just test at the tractor side connector to simplify it