I have been use this Komatsu machine in my constructions work. After a week operating in the field i choose to change to another dozer. In my opinion, this dozer is good but very hard when operate. Then i change to Mitsubishi that more smoother and calm. You can check my videos in youtube channel. Komatsu D21A : Mitsubishi :
Discuss this in the forum topic D21-A Opinions.