I have an acre of property, a lot of which is "lawn". I use the air quotes because it's green and needs to be mowed frequently, though admittedly a significant minority of it is green things other than grass, because I can't bring myself to be the stereotypical Suburban Dad that "takes pride in his lawn", i.e. spends real money on a service to spray chemicals on the lawn to make it more grass, and has a whole lawncare "regimen" that is religiously followed each weekend and season. I throw down some grass seed to fill in bare spots and otherwise hope for the best. I just can't be bothered to pretend that's important, and since I chose to live in an area with no HOA, no one else can force me to. Also, I'm on a well, and I'm certainly not interested in wasting my water keeping the grass I've potentially spent good money cultivating alive during a drought, nor am I keen on doing things to increase how frequently I need to mow it, and a large portion of my back yard is heavily shaded during the summer and heavily covered in leaves during a lot of the fall, so consistent, even grass is problematic at best anyway.
For the first couple of years I owned this house, I managed to convince myself that it was manageable with a self-propelled push mower, out of some mistaken notion of needing the exercise. After a bout with heat stroke, and realizing that I was wasting way too much of my weekend mowing, I decided to get a riding mower. I do not regret this decision, even when considered against the more typical method around here of paying a service to handle it.
My yard is probably 50% hills of varying steepness, some that are something you can mow side-to-side, (though there are some times when you have to shift your weight to the uphill side of the seat) others where you pretty much have to go up and down or diagonally across for fear of rolling the tractor. So I pretty much knew a zero-turn was right out, and I was looking for a traditional riding mower with a locking differential to manage the hills better. About ten-ish years ago, most of the mid-range riding mowers with hydrostatic drive had a pedal for a manual diff lock, but somewhere along the line, that had been replaced with either a lower-end diff that didn't lock (in the really cheap ones), or an auto-locking one in the higher end lawn (not garden) tractors. Pretty much across the board, that auto-locker was a Tuff-Torq K46 hydrostatic transaxle, unless you were stepping up to a garden tractor intended to pull ground-contacting implements. The right combination of price, features, availability, and not being an MTD with a nicer-sounding licensed brand name like 90% of the Cub Cadet, Craftsman, etc. available at the big boxes, plus no-interest financing led me to a Husqvarna YT42DXLS, which Husqvarna specifically claimed was well-suited for hilly applications, and given that it was roughly half again the price of the Lowes Depot variants, I figured more robust and reliable.
Worked great for the first 2.5 years I owned it, until a combination of some still-undetermined issue with a full fuel tank and the fuel/vapor system puking raw fuel into the air cleaner, hot exhaust, and dry leaves led to an engine stall followed by a fire that due to the distance from an available fire extinguisher led to a very melted front end and a total replacement of the engine. Fortunately for me, Husqvarna and Kohler stood by their product and covered what was probably half the cost of the tractor in parts and labor repair work under warranty. I've used it for another 3 years since then, though I do have a fire extinguisher mounted on the fender now. That brings us to last week, where a new problem presented itself. I sometimes mow only a section or two of my yard based on where the grass is long, but this time I did the entire yard at once. Toward the end of my mow, which hits the steepest part right at the end, it got slower and slower and more moan-y going up the hills until finally it would barely move itself under its own power on anything other than flat ground. No slipping belt noise, just the moaning that sounds like a bad power steering pump, which unfortunately means a transaxle issue.
Husqvarna maintains that this transaxle is maintenance-free, i.e. there is no fluid level to maintain, and no standard interval to change the fluid. Tuff-Torq equivocates a bit, as they do sell replacement fluid, and some variants of it do list a maintenance schedule, but after some research, I understand why - this is basically a sealed transmission. It has no drain plug or accessible fill cap, nor a filter. There is a fill cap with a magnet to collect spare bits of transmission out of the fluid, but because the transaxle is typically under the under-seat fuel tank, the only way to drain the fluid is to remove the transaxle completely from the frame, pry off the cap that is now exposed from the top of the case, and turn the transmission upside down to dump out the old fluid, which is usually traditional 10W30 motor oil. You might be able to use a vacuum fluid change system, but access is still going to be an issue, and you're unlikely to get all of the fluid that way. So they're right, it's not exactly consumer serviceable in the way that one might expect a homeowner to change the oil, air filter, spark plugs, etc. Seems too good to be true, but service intervals on lots of stuff have been getting extended and simplified because of higher quality lubricants, better designs etc. so I guess it could be plausible, right?
No, dear reader, our instincts are correct, it is basically too good to be true. The internet is pretty full of sad stories about this transaxle failing exactly like this after a low triple digit number of hours of what should be typical use in a variety of brands and models of riding mower like this. Some get repaired or even replaced under warranty, but I'm well outside my warranty period. Turns out that this transaxle has a bit of a design flaw that a cynical person might look at as a very clever way to make these things cheaper to build, and ultimately more disposable when they fail after some number years of use that is >= the warranty period. Since things expand when they get hot, this transaxle has a breather that will allow fluid to escape instead of pressurizing and blowing out a seal or the fill cap. The act of using it to carry my considerable avoirdupois plus a full tank of fuel up a 25+ degree incline, or across a slightly less severe (15-18 degree) incline for long periods of time, especially in the heat of summer, means that it's probably burping out fluid pretty consistently, that then collects along with the grass and leaf dust as greasy schmutz all over the cooling fins, making the overheating problem worse, which causes more fluid foaming and venting, and basically cooks the transaxle. Those same forums and YouTube videos have hopeful stories about people managing to resuscitate them by swapping the fluid for synthetic 5W-50 (which is what TT sells on their site as replacement fluid) after draining considerably less than the factory fill out of them, cleaning the fins, maybe swapping the drive belt, but also those who did that, had no improvement, and had to crack the case to replace the internal parts that had worn prematurely due to overheat and lack of lubrication. The rebuild kit, if you can find it, appears to be almost $500. The replacement transaxle is closer to $1K. So despite the fact that I have an engine with less than 60 hours on it and a perfectly functional mower deck, I am somewhere between maybe being able to do major surgery to get it functional enough to sell to someone with a flat yard, and selling it as-is to someone who's looking for a donor engine and/or mower deck for a project. I figure that even if I fix it, my yard means that the same problem exists, and I'm basically signing up to tear the thing apart every season or two to change the fluid, plus the existing accelerated wear likely means that the next time this starts happening, it'll be necessary to start throwing expensive parts at it.
I am still waiting to see if I can limp it along to use it for short periods of time before it overheats, or if it is far enough gone that I am going to be back to push mower for a few weeks or what, but the long-term fix is that since my dad has hired a service to tend to his several acres, he is going to sell me his now-idle Kubota GR2100, which is a small (I think 4WD) diesel lawn and garden tractor that is probably much better suited to my terrain and one or two notches up in terms of the heavy-duty vs medium/light duty and prosumer vs residential spectrum compared with my current problem child.
