I have this issue with my Aussie HRR216K9VYUA, and I pulled the box/axle assembly out to have a look after digging through this thread, thanks for all the detailed discussions. This issue started happening maybe when the mower was ~3years old only, now it is only about 5 or 6 years old and I only use it about 4 weekends per summer/sping! The shafts weren't too scratched up, and looking at the bushes, there is a tiny bit of axle to bush play (suggesting maybe this mower is new enough to have the so-called updated bushes with the oversize hole?). I find with the assembly out, turning the shaft by hand has a bit of resistance in the transmission, which looks to also be a contributing factor. When I push the axle into the box at the same time as turning, I can feel something inside the box giving a ratchet like noise and more binding than not putting any sideways push on the axle and rotating. When using the mower, like most in this thread have mentioned, the issue gets worse when used for 15mins or so, suggesting perhaps when the oil in the box is warmed up that this could be part of the cause.
Am about to disassemble the box to see if there is anything inside that can be freed/improved, I might throw some synthetic 10W/30 into it rather than the Honda mineral 10W/30 engine oil, has anyone had any issues using synthetic oil in the box?
Trying to find a new shaft/box online to purchase here in Australia (at a reasonable price) is impossible, I can't believe it is like $60US or so, but about $300AU here (half the price of the mower!!). I see there are 2 part numbers-
Buy Honda 20001-VL0-S00 ( replaces 20001-VL0-P00) Transmission Assembly; Made by Honda: Automatic Transmission Assemblies - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
www.amazon.com
Honda 20001-VL0-S00 ( replaces 20001-VL0-P00)
The picture at the amazon site shows cooling fins, mine doesn't have those fins, but essentially looks the same, so I am guessing I have the 20001-VL0-P00 part number & this looks like mine-
Is there any improvement in the S00 vs P00?