https://www.facebook.com/tom.carmelengo/videos/991518370889686/
It seems that one of the final drive gear sets failed, and had to be replaced. You can see the drive Sprocket/Hub assembly on the ground, and those are way tough to get loose, often needing another Tank to hook up to them, and take a running pull (at least that’s how we did it in the days of old. )
Friend of mine was a tank mechanic.
Always commented that nothing weighed less than a hundred lbs.
Particularly the tools needed to fix them.