I was already commenting that he's not wiggling the machine with tracks when pulling with bucket, but then he got it in the end. Also if the machine moves back and forth, simply picking large rocks in front of the tracks, then pulling the machine over these and repeating this on the other side would have helped. But of course easy to comment, when not in the operator's seat. I've been in similar situations many times before, especially when cleaning/digging drainage ditches.