Recently ran across a widow woman that had her late husband's D-4 for sale. Could not find a serial number and having limited knowledge on these dozers, but I can tell you it had a pony motor, a wench, and a straight blade that could be angled manually. Undercarriaged looked close to new. And she stated he had redone the undercarriage and put clutches in it. ( assume Steering). She said it last ran a year ago and did have a new battery, but it was dead of course. She wants $6000 and in Lawrenceburg, TN. It has been stored under a shed. Contact Mrs. Clifton- 931-766-6672.