At least to me.
I was looking around on www.cimorelli.com. I wasn't looking for anything in particular and happened to open a file labeled as the 1927 TT Parts Price List. To my surprise the file was was obviously a few pages from a larger publication and only covered TT parts for 1918-19.
What I found interesting was that the pictures showed the early clam shell with the beads at the axle tubes, only the low speed rear end gears, and the single shaft differential with 2 spider gears (the spider with 4 gears obviously came a little later). This is the first document I've found that actually seems to say the features I mentioned didn't appear until at least the 1920 year model.
Something else that's very interesting. At the top of each page it reads, "ALWAYS GIVE THE TRUCK NUMBER WHEN ORDERING PARTS". What truck number? It doesn't say "engine number". Could it be that the early trucks were serialized, or perhaps Ford intended to serialized them but didn't get it done?
I wonder if this explains the 6315 that's stamped into the top edge of both clam shell halves on my TT. Maybe they started production serializing them but discontinued it shortly after starting production??
Did you get a contact for ordering these parts ?
I have my truck number, but who do I tell ?
Interesting. Many years ago, I had one of those early TT rear ends. I did not use it because I had figured it was not correct for the '25 truck I had and restored. I eventually sold those parts, but have long since begun to regret that. Turns out, that early rear end is rather rare.
Thank you Henry P for sharing this information you found. The early TTs are different, and reliable information is not easy to come by.
Drive carefully, and enjoy, W2