Thanks for all the interest, everyone. I enjoy reading your comments on these great old machines.

Thanks, Brad! I had fun making this video on some "small equipment". So much so, I made an X700 one, will post shortly. Take care.

57Dalv - Really liked your comment. These old 400 Series tractors are great machines. With a few upgrades to fix some annoyances and LED's + HD Field Trax tires, you basically have an X700 for 1/4 to 1/3 of the price. I also sort of prefer the nostalgia, charm of the FD620D, and baby ten series styling.

Hello sir, glad you watched the video and glad to hear from all of you 400 Series fans. I had a guy comment on one of my other videos that he'd rather listen to the Trump-Biden debate than me. I guess he just wanted to know how to change the part and not learn anything about it. I can tell you are curious and want to learn, which is great and why I started this channel. So, the Kanzaki K91 is an HST with internal charge pump. The charge circuit firstly keeps your low side loops happy and any excess is then available for steering and the implement system. The steering and implement valves are both open center. If you're not steering, the excess flow heads out the power beyond port to the implement. The return circuits from both the steering and implement valve tee together at the RH side of the lower radiator tank. Eventually all of this excess flow ends up there and averages the supply, although dynamically it will can change due to cylinder ratios. There is an oil section of the rad that cools this fluid. It leaves the LH side of the tank and dumps back into the K91. If you poke your head underneath, you'll see two -6 ORFS connections with on that lower rad section, those are the cooling lines. The 445/455 is a very robust, well designed unit and I've never seen them leak, so most people don't know they're there. The later X495/740 changed from this design to a little standalone cooler in front of the rad. Those look like one of those little Samsung units you see on heavy equipment, and uses crappy beaded hose connections. I've repaired several of those and it's a huge mess because the fan sucks the oil through the rad and blows it all over the engine. Since you're curious, I'd like to pose a quick thought experiment. Let's ignore the charge pump heat and just consider the HST pump/motor for simplicity. Let's say you're in a heavy drawbar application like tilling and propel is consuming 11Hp and the rear PTO the balance (11Hp). This isn't a heavy equipment trans that is 90%+, it's a light duty bullet nose style, so let's say it's 85% efficient on the pump and motor. (.85 * .85 * 11) = 8 Hp going to the ground and the rest, 3 Hp ends up as heat. 3Hp = ~7600 Btu/hr. To put that into perspective, this would be 1.5x of those 120V ceramic bathroom heaters, chugging away directly into the center of your trans. It must be cooled or you'd have Chernobyl on your hands in no time. The K91 and and your commercial zero turns do it this way (the right way). You've probably seen those cheesy plastic fans on the cheaper throwaway HST's on box store riders and zero turns, which in my opinion is a poor excuse for cooling because most people don't clean them and HST life greatly suffers. Point is, either way they need to be cooled in some way to live. Happy wrenching!

Holy cow, $450 is a screaming deal for a '00 445! It's sort of "Deere country" here in my area, and I never see them go that cheap.

I have a 48" deck with the power flow head I don't need. I am in northern Michigan. I have used a couple of the anti-scalp wheels on my 54" deck so they are missing.

Hello, I looked back in my notes and had written down that the issue was fixed starting at the 1998 model year, serial numbers 60001 and later. I also had a note for the engine S/N itself which was 150198 and later. I haven't owned one that got extremely close to the S/N break so can't confirm personally, but haven't run into a situation where those numbers were wrong yet. On the gears, I pulled up some pictures of the last failed one I repaired. The actual issue is the cam gear which usually breaks during initial cranking, but when it happens the broken teeth get jammed up in the other plastic gears and sometimes break them too. I usually see the loose teeth break the oil and water pump gears as well, but not the governor.

Perhaps you mean push mowers. I'd like to reply to this one because I want our viewers to know the facts. The X-Series riders (sold at JD dealerships) and I think Gators and tractor mounted snowblowers are made by Deere at the Horicon, WI plant. I have personally been to this facility and have seen production, engineering, and their test facility. I'm most familiar with this location because it's in the Midwest and close to where I live. A great, hardworking bunch of assemblers and engineers work there producing these USA made products. There is a KZfaq video showing production and the test site. This was exactly what I saw when I visited: kzfaq.info/get/bejne/m6iPY5VjqrC2nn0.html I believe the big box store stuff like the 100 Series are made by Deere in Greeneville, TN. I haven't been to this facility yet but heard they really crank out the products, very high production disposable mowers for the box stores to compete against the Crapsman, MTD, Scrub Cadet, etc.. Deere also makes zero turns, commercial, and turfcare related products for things like golf courses. I haven't been to this facility either but know that it's also a genuine Deere factory, located in Fuquay-Varina, NC.

Is it the same gear he is talking about in this video or another gear we need to be mindful of? Where can we get more articles or information on the serial numbers that were affected?

At time 5:15, you can see the Oil Pump and Governor Gears in the front cover, the Cam Gear is in the engine.