Need help Identifing old D6

Hi, I just found this site and I hope someone can help me out. I just bought a D6 The tage on the left rear of the diff houing is missing but it has the number 44A7280 where the tag was. To the right of that is a tag the gives the Transmission group number 5M 2944. It has electric start 24 volt, hand clutch, 12' cable operated blade. On the left side of the engine the tag reads ser#99E9893 Right below that is a second set of numbers it looks like the first digit has been over stamped maybe a 2 followed by R8593 Motor Grader. This was from a goverment auction.
Can somone tell me what year this was made?
Thank you,
Jim

Sounds like a D6B from the early 60's, with a 99E motorgrader engine also from the early 60's. Good luck with it. Charlie

D6B is 1962
99E is 1964
Don't recognize the xR8593??

About the only engine difference is the grader is a two section oil pump/sump arrangement and the tractor is a three section...hope they changed it over.

Thank you for your help. Jim