I have had 3 Cub Cadets, and only 1 good one. I had an old 700 series that had a kubota diesel, now i know this is a tad smaller than the legacy, but not much. I have since gotten rid of my 2 newer cubs, both were possibly the worst diesels i have ever had to deal with, neither 1 started in cold, neither 1 stayed cool enough in the 80 degree temps, just not what I expect when I spend good money on equipment. My 5264 had the same problems as your cubs did, I can say after owning 3 different machines with daihatsu diesels, they aren't nearly the caliper of kubota or yanmar diesels, my 3rd machine besides my cubs that had a daihatsu was a simplicity legacy, I purchased it for my grand father, he has had multiple strokes and really all he can do is mow the lawn, so i figured a good large from garden tractor would be good, and I love diesels, I have them in all the machines i personally own. The machine itself was wonderful, great fit and finish, very comfy, but the diesel was my worst nightmare. My grandfather isn't very patient, and he shouldn't of had to be with the amount of money i spent on that machine, I took it back to the dealer a total of 9 times, on the ninth time after only putting 10 hours on the machine i got my money back.
Now for the problems I had with my simplicity engine. It leaked like a sieve, none of my other diesels have done that, so I don't know why it did, it leaked everything, oil, coolant, the whole nine yards, its as bad as a jaguar. Next, the block cracked, I assume this was to either not having enough coolant because it leaked so much, or it was flawed from the factory, either way this shouldn't have happened. Thirdly, the coolent pump, and the oil pressure pump went out as well, couldn't tell you why this one happened (note to this point the tractor has been back to the dealer 4 times). At this point I brought it to my home and mowed myself, I couldn't even get it to start, come to find out when they put the new water pump in, they somehow shorted out the starter, so I took it back to the shop (5th time). Luckily, (i use that term lightly) they happened to have a starter in stock so they put it in and she fired up, back on the trailer to go home. I get home, and I unload the machine off the trailer, and I see this puddle of oil & coolant, knowing that this has happened already, I call the shop and they tell me to bring it back and they will give me a loaner machine (6th time). So, I wait for a few days and get the call my block has cracked again, it will be another 2 weeks before its all put back together. I get a call that its done, I go pick it up and take it home (only ten minutes away), and mow, its the first time i have gotten to mow with it, amazingly i thought it was fixed, and it mowed really well, so I mow another 2 acres or so and i hear this horrible pop and my mower deck shaft flys out the side of my tractor, i knew from this point it was hopeless. I called the dealer, they were in shock, so much so they even brought me a loaner and took mine back to the shop, they call me to give me the verdict, it did 2200 dollars worth of damage, and that was only in parts (7th time). So after another week of waiting they bring me back my simplicity, i have to hand it to them, they get it fixed fast. I go to the dealer, and don't even bother to take it home, i just mow their grass, and within 10 minutes my mower deck shaft box was cooked, it wasn't set right, because they were sent a just slightly bent arm from the factory, this i understand (8th time). Finally i come home and its sitting at my house. I had hope for it, I really did so i got on it and mowed, even mowed my whole lawn, I thought it was really ok, it was cutting well, not leaking, staying cool enough, i thought i was done, boy was i wrong. I put away the mower in my garage, and went inside and went to bed. I go out to my garage the next morning, the lawn mower was soaked in oil and coolant on the whole engine, couldn't tell you how it happened, i called the dealer, they had a check for me the next day for the amount of the machine plus some. To this day no one has figured out what was wrong with that mower.
I know that this is just a bad lemon happening, but the point is i had problems with all my daihatsu diesels. If you decide to go with the simplicity, i suggest to be on a good happy easy drive route to the dealer, if its anything like my ordeal, its always good to have a decent drive while cooling down.
If you want a diesel garden tractor, get something with a Yanmar or a kubota diesel, thats my only suggestion, I have owned machines with alot of different diesels, these 2 seem to be the best. Good Luck
