What model grader am I looking at here?

Hi folks,

I have a good friend that looked at an old grader the other day. I haven't seen one like it before but I'm no expert by any stretch. It somewhat looks like a No.11 but the drawbar is channel and looks older. It also has a D4400 rather than the D6600. The motor unit looks to be a different shade of yellow. Any chance the D4400 was retrofitted? It just looks a little unfinished how it is installed. When I did a little research, I found out about a No.10 Tandem Diesel grader. Could this be one of them? Thanks friends. 

Mangoman
 

The #10 Auto Patrol, tandem, 1937 - 39 uses the D4400.

The serial number is stamped on the brass tag above the left front wheel in your photo, on the web of the frame channel. That will ID it.

Yes Eds, I will refer my friend to check. He didnt get that info but that will positively identify what we are looking at. I just thought I might get some preliminary info from more knowledgeable folks. Thanks

interesting fuel filter arrangement.

Should be a 2Kxxxx s/n, same engine as RD4.

Hi Team,
the fuel filter is the standard edge type brass plate stacked canister that are a cleanable elephant strainer of the day---see scan below from a D4400/D4 fuel system.
Cheers,
Eddie B.

So, my friend got back out to look at the grader. From what I can read it says 9F1616TS. What does TS mean if that is what I am reading? From what I can see 9F means Auto Patrol No.10 It also looks like there were No.10 graders with the D6100 3cyl as well as the D4400? Anyone have a better idea of the actual year of this thing, and also about the "TS"? Thanks!