While trying to date the rear end, what I did find for dating a Model TT rear end was that the Model TT Truck were made from 1918 to 1927, but also there were some Model TT Trucks made after 1927. Also, some believe the Model TT Truck was made in 1917, but a corroding to the records those were 4 prototypes. So, my opinion there are really no 1917 Model TT Trucks that would have been sold to the public. So, the 1917 Model TT Truck would have not really have been out there (Ford would have not sold them). So now looking at the rear end I have, here is a list of the differences of this rear end:
First, there are the ridge beads that run around the outer edge of the casted gear housing (pumpkin). Where the casting meets the straight axle housing pipe.
Second, the rear worm gear cover cap does not have an oil filler plug. Real early trait.
Third, the bolts from the rear worm gear cover cap does not go through the casted gear housing (pumpkin). The casted gear housing (pumpkin) does not have the hole going all the way through the casting.
Fourth, there are a set of matched numbers stamped on each half on the top of the casted gear housing (pumpkin) at the end where the rear worm gear cover cap is. This has brought up an interesting discussion in other talks on this website. Those numbers show up on early rear ends and those numbers that other people have are not the same (so it is not a part number). So, looking and reading what has been collected, I would speculate that those number are serial numbers on the early rear ends (which that practice was stopped in 1918/1919 sometime). Maybe it was on only the 40,000 that were produced in 1918 where most of those Model TT Trucks were sold to the military. Or those numbers were to match the left and right halves during the machining and production of the early rear ends. I am not totally sure what they were for.
Fifth, the brake plate is also attached with a rivet to the rear end. Look at the bottom at the rear end where the axel comes out and the brake plate attaches and there is an extra cast piece with a rivet.
Sixth, the radius rods ends where they attach to the torque tube are larger.
Seventh, in the internals there is only a two-gear spider.
Eighth, in the internals the drive shaft end splined grooves are shallower as well as the grooves in the coupling.
First, there are the ridge beads that run around the outer edge of the casted gear housing (pumpkin). Where the casting meets the straight axle housing pipe.
Second, the rear worm gear cover cap does not have an oil filler plug. Real early trait.
