[PNM46]

My L120 has 350 hours, but my yard is 2 acres, hilly - lower side maybe 15' below high side. I have some steep banks that I used to go up with confidence.

Now, once the tranny gets hot - maybe half way through the yard - it will not go up level-with slight grade.

If I let it set for a few hours - to cool off - I can finish the near level part of the yard without any problem.

About 5 years ago, I removed the tranny and dumped the oil. There was no metal on the magnet. I put in new oil and a new fan and continued to use until now. I probably used JD tranny oil.

Seems to me like the hydrolic pump is getting tired. Do you think it would benefit from replacing the oil with 5-50? Or, do you think it is time for a new K46AC or maybe better.

Thanks for your wisdom.

 

[Alien5044]

Nothing to lose in trying a little higher viscosity oil, but not sure the L120 is a good match for any hilly lawns. Asking it to work on 2 hilly acres is probably beyond the designed endurance of the K46. Others with more JD K46 experience may chime in with further advice.

A quick look at Amazon and they aren't cheap although not sure these are correct for your L120. And if you find a used one, who knows how much life left in that on 2 hilly acres.

Good luck with it.

 

[ST1100A]

The K46 is an entry level very light duty transmission. It is not designed for the hills you describe, and mowing a 2 acre lot is a lot of work for that transmission.
If you got 5 years of work out of it, it lasted very long and is at its end of life by now.
You would want something with a minimum K71 or greater to do the work you describe, especially with the hills.
It got a lot of hard service out of it from what you describe, and now it is worn itself out to the point of replacement.
That transmission is really only designed for small flat level yards without hills. When it gets hot and the metal pistons and cylinders of the pump and wheel motor expand, hydraulic pressure drops and the tractor doesn't want to move, it has to sit and cool down so it moves again.
The only thing you could do to get a little more time out of it would be to replace the oil in it with some pretty heavy weight oil to help it a little bit. Oil like a straight 60 weight or higher, but that's only a temporary fix, and it will fail all together soon.
It's basically time to upgrade your tractor to a bigger heavier unit on the Garden Tractor scale.
What you have now is a light duty Lawn Tractor. You got a lot of time and work out of it for the hard use you got out of it.
If you're a John Deere fan, you're probably looking at an X 500 series tractor to match your needs of the type of work you are doing with it to get longer service life out of it.
Some of the J.D. guys will probably chime in soon and give you some good recommendations on what series would work the best for you for the type of lawn size and hills you have.

 

[Frogmore]

It does sound like you have worn out the transaxle. There are no cheap, easy solutions that will last. The easy solution is to buy a machine with a much better transaxle, because clearly you need one. This solution is anything but cheap. You need to start looking at the X500 series. If the banks are really steep, you might actually need AWD, which means the X700 series.

 

[Frogmore]

The other option is a rebuild or replacement of the current transaxle. It probably would last about as long. Or you could upgrade the transaxle. None of these are in the easy category, but some are cheaper than buying a new machine that is up to the task.

The other choice is buying a used garden tractor. That is cheaper than new, but comes with its own set of risks.

 

[jlhappypappy]

Nothing to lose in trying a little higher viscosity oil, but not sure the L120 is a good match for any hilly lawns. Asking it to work on 2 hilly acres is probably beyond the designed endurance of the K46. Others with more JD K46 experience may chime in with further advice.

A quick look at Amazon and they aren't cheap although not sure these are correct for your L120. And if you find a used one, who knows how much life left in that on 2 hilly acres.
View attachment 2562981
Good luck with it.

I have a trans that i bought for my L-120, but sold it insted. The one I have is out of a J D 325, you can have it for what I paid. $200.00

 

[Harry Ferguson]

My L-120 did the same at about the same hrs. I purchased an OH kit for the transaxle online, with pump, motor, seals, side gears and spider gears. Filled with the fancy synth oil they sold me but it needed more to be full so I topped up with Mobil1. It worked fine. After one more summer the engine developed a flat exhaust cam on one cylinder so I parked the machine as a parts stash. So far I have used both drive belts on my new E-170. The transaxle will fit if I ever need it, and also the four new tires. Bottom line: The O-Haul was a success but the patient died. I should mention, the L-120 had a bad habit of picking up gravel from my driveway with the rear tire treads and tossing it into the transaxle cooling fan under the seat. I often found the fan with no blades and kept a spare on hand but the trans overheated repeatedly. The dino oil it comes with is a death sentence.

 

[Aluvaboy]

The K46 is an entry level very light duty transmission. It is not designed for the hills you describe, and mowing a 2 acre lot is a lot of work for that transmission.
If you got 5 years of work out of it, it lasted very long and is at its end of life by now.
You would want something with a minimum K71 or greater to do the work you describe, especially with the hills.
It got a lot of hard service out of it from what you describe, and now it is worn itself out to the point of replacement.
That transmission is really only designed for small flat level yards without hills. When it gets hot and the metal pistons and cylinders of the pump and wheel motor expand, hydraulic pressure drops and the tractor doesn't want to move, it has to sit and cool down so it moves again.
The only thing you could do to get a little more time out of it would be to replace the oil in it with some pretty heavy weight oil to help it a little bit. Oil like a straight 60 weight or higher, but that's only a temporary fix, and it will fail all together soon.
It's basically time to upgrade your tractor to a bigger heavier unit on the Garden Tractor scale.
What you have now is a light duty Lawn Tractor. You got a lot of time and work out of it for the hard use you got out of it.
If you're a John Deere fan, you're probably looking at an X 500 series tractor to match your needs of the type of work you are doing with it to get longer service life out of it.
Some of the J.D. guys will probably chime in soon and give you some good recommendations on what series would work the best for you for the type of lawn size and hills you have.

I used to have a Scotts L2048 mower which was fitted with a K46 TuffTorq transmission. I mow an acre property with some inclined terrain. I bought it in year 2000 from Home Depot. It has clocked 923 hours. I changed the transmission oil to Castrol 5W50 oil and has replaced the oil twice so far in its 22 year life. It is still going strong. (I sold it to my friend and he still uses it). I have since acquired a used X300 which originally had a K46. The X300 only had 68 hours when I bought it. I sourced a K66 tranny from Surplus Center (an online seller) and has since replaced my K46 with K66. My X300 is now about 300 hours and still going strong!

I gave my scenario just to counter your statement "If you got 5 years of work out of it, it lasted very long and is at its end of life by now".

 

[Frogmore]

The definition of steep varies. Google (via Oxford) says:

(of a slope, flight of stairs, angle, ascent, etc.) rising or falling sharply; nearly perpendicular.
"she pushed the bike up the steep hill"

But most people are not very precise by what they mean by steep. I live in the foothills. Steep means 40° or greater. My 15-20° slopes are just rolling hills to me. But they are actually considered steep by most transaxles.

In the plains, 10° might be considered quite steep. But, most transaxles can probably handle normal usage on a slope like that.

In any event, @PNM46 hasn't provided much information on the degree of slope. Based on results it seems like the L120 was not up to the task. The L120 has the same K46HD that the X300 does. Mine has been fine for 15 years and 350 hours, so experiences do vary.

 

[PNM46]

I used to have a Scotts L2048 mower which was fitted with a K46 TuffTorq transmission. I mow an acre property with some inclined terrain. I bought it in year 2000 from Home Depot. It has clocked 923 hours. I changed the transmission oil to Castrol 5W50 oil and has replaced the oil twice so far in its 22 year life. It is still going strong. (I sold it to my friend and he still uses it). I have since acquired a used X300 which originally had a K46. The X300 only had 68 hours when I bought it. I sourced a K66 tranny from Surplus Center (an online seller) and has since replaced my K46 with K66. My X300 is now about 300 hours and still going strong!

I gave my scenario just to counter your statement "If you got 5 years of work out of it, it lasted very long and is at its end of life by now".

Do all of the connections work without modification on the K66?

 

[PNM46]

I used to have a Scotts L2048 mower which was fitted with a K46 TuffTorq transmission. I mow an acre property with some inclined terrain. I bought it in year 2000 from Home Depot. It has clocked 923 hours. I changed the transmission oil to Castrol 5W50 oil and has replaced the oil twice so far in its 22 year life. It is still going strong. (I sold it to my friend and he still uses it). I have since acquired a used X300 which originally had a K46. The X300 only had 68 hours when I bought it. I sourced a K66 tranny from Surplus Center (an online seller) and has since replaced my K46 with K66. My X300 is now about 300 hours and still going strong!

I gave my scenario just to counter your statement "If you got 5 years of work out of it, it lasted very long and is at its end of life by now".

I suspect mine is worn out. It is over 10 years old, even though it doesn't have that many hours. I was pretty rough on it. I believed the JD commercial where the guy on a JD lawn tractor went into the weeds over his head then came out the other side
The normal grade on 1/2 of my lawn is 10-15' over a 100 ft distance. But on each road front I have steep banks created by the road builder. I would guess the grade is about 45 degrees for 10-15'. I used to mow these grades once per month in the summer, going straight up about 15-20 time each. The tranny would just dig in, sounded like it went to a lower gear, and went to the top. One tough little dood. But - MAYBE - I over did it
So, shame on me - and the JD commercial

 

[PNM46]

The other option is a rebuild or replacement of the current transaxle. It probably would last about as long. Or you could upgrade the transaxle. None of these are in the easy category, but some are cheaper than buying a new machine that is up to the task.

The other choice is buying a used garden tractor. That is cheaper than new, but comes with its own set of risks.

You are right on my real issue. I am almost OLD. I don't know if it is financially smart to buy a tractor that will survive cutting this yard for 20 years. I'm thinking an upgraded transmission or used or, maybe even, just paying some dood to mow my yard a few time each summer.

 

[Frogmore]

There is a big difference between cutting even 3 foot high grass on level ground and just traveling up/down a steep slope. 45° is not just steep, but so steep that you need very specialized equipment that typically costs $30K or more to buy new.

15% (15 ft over 100 ft) is less than 10° and is probably fine for the K46 in your machine. I am not convinced the K66 would survive the abuse of 45° slopes for much longer than the K46 did.

Unfortunately, there are no good and easy solutions to your problem that are not expensive. You could buy another 100 series machine and avoid the 45° slopes and it would probably last as long as you wanted it to. If you want a machine that can handle the 45° slopes for more than a few years it will be very expensive.

 

[Frogmore]

How old are and how long do you expect to be living where you are?

Where do you expect to be living (or not) when you are done with where you are?

A used machine will typically hold its value well. A high quality new machine less so the first few years, but after that really well typically. Either you (or your heirs) can sell the machine when you are done.

If you are only planning on being there 5 years, just buy another disposable mower. If you are going to be there 10 or more, investing in something good is probably wise.

 

[PNM46]

There is a big difference between cutting even 3 foot high grass on level ground and just traveling up/down a steep slope. 45° is not just steep, but so steep that you need very specialized equipment that typically costs $30K or more to buy new.

15% (15 ft over 100 ft) is less than 10° and is probably fine for the K46 in your machine. I am not convinced the K66 would survive the abuse of 45° slopes for much longer than the K46 did.

Unfortunately, there are no good and easy solutions to your problem that are not expensive. You could buy another 100 series machine and avoid the 45° slopes and it would probably last as long as you wanted it to. If you want a machine that can handle the 45° slopes for more than a few years it will be very expensive.

Thanks for your comments. After reading the comments I just wanted to level the playing field by explaining what this little JD has been through. I no longer cut the steep slopes with the tractor. I pay a neighbor to do it with a weed eater.

But I would still consider buying a new transmission because I think the mower is good for a few more years.

I would consider stepping up to a "stronger" transmission if it were to fit with little on no modification to my L120.

 

[Frogmore]

There are many variants of the K46 and K57. The K57 is slightly better, but basically the same as the K46 (it has a charge pump as the main difference).

The next level up is the K58. It has 1" axles a as do the higher up versions, so more adaptation/cost is necessary.

A lot of people have put in a K66. It is actually a low end garden tractor transaxle. It requires quite a bit of adaptation to fit, especially for the 100 series, which needs the go lever the opposite direction of the X300 series machines.

You can buy a kit including a K66 for your machine. It would include all the parts and decent instructions. It is about $2500.

About the K66 Upgrade Kit - RJR Tractor

The K66 Upgrade Kit is a complete DIY solution for your old transaxle. Install a new K66 transaxle in your tractor in about an afternoon with basic hand tools.

rjrtractor.com

While that sounds really expensive (and it isn't cheap) it isn't a bad value if you place any value on your time.

But, $2500 would buy you a new box store mower.

Deere probably charges close to $1K for the replacement transaxle for your machine. You can get it cheaper from other sources, probably saving $200-300. You can get a random new K46 for about $400 from here: K46 Tuff Torq 7A646084591 Hydrostatic Transaxle Transmission | Hydrostatic Transaxles | Transaxles, Transmissions, Differentials | Power Transmission | www.surpluscenter.com
It is not exactly what you need and might need to be adapted to go forward instead of reverse.

As I said originally there is no cheap and easy solution. You need to decide your budget and the amount of work you are willing and able to do. If you need to take it to the dealer, it will be cheaper to just buy a cheap replacement machine.

 

[Rarefish383]

When I bought my 52” Snapper Pro walk behind with a 20 HP Kawasaki twin, the owner let me take it to my shop to have it checked out. My shop owner said he had no problem taking in any equipment with a Kawasaki twin with 1000 hours on it for trade, unless obviously abused. When I killed my L120 my JD dealer said the average 1/4 acre home owner put 40 hours a year on their mower, and the L series was designed to do that for 10 years, or about 400 hours. It wasn’t designed to explode at 400, but if you got that, you got what you paid for. So I took what my shop owner said to heart, and bought my X540 with 7-800 hours on it. So at 400 hours one unit is a senior citizen and at twice the hours the other unit is a teenager. I have a 265 with a 17HP Kawasaki Single and Sundstrand rear with 3000+ hours. That Sundstrand is a good rear. Something we often over look when taking about they life spans of the rears is the time saved mowing with the heavier tractors. My X540 with the 48” it came with would run circles around the old L120. Now with the 50”, it’s not even a discussion. Then throw in a 2 acre lot, that time saved is substantial. I did post pics of my X540 mowing hay higher than the hood on my field in WV. I did that several times with my old 265 and it was low on power for the job, I had to mow slow for it to clear the grass from the deck. It took 2, 4-5 hour afternoons to do it. The X540 did it all in one 4-5 hour afternoon. Now the field is under control I can run WOT. Long story, I’d find a bigger used machine.

 

[Aluvaboy]

Do all of the connections work without modification on the K66?

I had previously posted in 2018 my swapping out of the K46 to K66. I have included pictures, prices etc.from that time. All connections worked without any modification on the K66. But I replaced the Hitch Plate on my X300 to have an easier swap out. I have described everything in my 2018 post. The rear tires had to be replaced as well along with the hub.

 

[Frogmore]

Yours is a great thread. I used it for inspiration. But, @PNM46 has a 100 series machine. They are different. They use reverse direction on the go lever. So you need the K66R not the K66Y, or you can put a reversing lever in the mix, or you can take the transaxle apart and flip the part you are not supposed to flip when rebuilding.

The frames are also different, so some adaptation might be necessary. People have done the swap, but it not a simple bolt on job.

It seems @PNM46 has soured on Tuff Torq. I think judging a company or person based on the worst thing they have done is not very fair, but it is fairly common.