I had a messy but fun time pulling the Tuff Torq tranny off that old JD455.
I've been working on the assumption that the shade-tree guy who welded the tow valves shut actually caused the "no reverse" problem it has. Now, I'm pretty convinced.
There were a couple of case leaks, so that offered an opportunity to peek inside with good reason. But when I got the case open, I was completely amazed.
This thing has 3K hours of actual mowing on it. There wasn't enough swarf inside the case to dirty one fingertip! If I didn't mind the taste of ATF, I could've eaten out of it.
Now I'm completely convinced that nothing is hanging up or broken in there. The only wear I could see at all was a high mirror polish on the tips of the PTO gears. The differential didn't show any wear beyond break-in that I could detect.
The schematic shows that the hydrostatic circuit gets its fluid charge from the two check valves he welded shut... duh! Why didn't he just replace the o-rings that were leaking??????
The two valves are spendy, running over $350 for the two, but I think it's a worthwhile expense. Since one of them is also a pressure releif valve, I thought better of fabricating them... the charging pressure really should be correct.
So, I've buttoned it back up, sans leaks. More when the valves arrive via slow post.
LLoyd