Over the Christmas holidays I spent my time cleaning up two TT rear ends. I found these two different differential spider gears. Can anyone put a date to these?
The rear end with only two spider gears is earlier. There's a reference to a difference between 1918-21 and later TT's in Dean Yoder's web page here: http://www.ttyoder.com/TTpage-2.html so perhaps the change was in 1921?
My '23 has the second type with four gears. I haven't been into the '15 yet.
According to Bruce McCalley's "Price List of Parts" [contained on his "Model T Comprehensive Encyclopedia - available at: http://mtfca.com/encyclo/mccalley.htm or from the vendors ] The Ton Truck (TT) rear axle used the two spider gears 1918-1923 and went to the four spider gears 1923-1927. So sometime during 1923 model year -- not sure of the actual dates and not even sure if TT chassis had a model year prior? Probably with overlap - not sure how much overlap.
Hap l9l5 cut off
OOoops! I didn't notice that it was TT. Disregard.
I believe (not positve) the TT chassis had only 1 change during its entire production. At about the same time as the rear end went from 2 to 4 spider gears the chassis rear cross member was made a little longer and with that extra length went from 1 body mounting hole on each side to 2 on each side.
As far as I've been able to learn, that's it. No other changes were made. Anyone out there know better??? I'd be interested if you have more or better information.
A favor please, if you don't mind - Would you take a look at the housing the 2 spider gear set-up (the older one) came out of and see if there are any numbers stamped on the very top of the clamshell halves, at the rear. Mine have a machined smooth surface at this location with the number 6315 stamped on each half.
I've tried over the years but never been able to find another one with numbers stamped on them. My truck is an early '18, I think. It has a later engine, so I had to rely on other clues, like the patent plate, the 2 screw horn button, the short runing boards, the chassis short rear cross member, wood firewall without a choke hole, the front spring clamp, etc. to estimate the year of production. I suspect there was an early effort to serialize them, but have never been able to confirm that theory. If I'm right, it would make my truck a very early '18.
Thanks for any information you might come up with!!
When I got home last night, I checked the spider gear housings. I found a part number of TT11 on the castings of both halves. There was nothing on the machined surfaces. There was also the number 5 stamped on one of the halves. Hope this helps.
Thank you for checking! My stamped numbers are still a mystery, but I appreciate your help.