MODEL TT truck Early Late DRIVE SHAFT Comparison rear end splines

[StevenS]

There have been a few times that this has been mentioned in this web site, so I ran across this case and took some pictures of it. There are four pictures of drive shaft splined ends and couplings for a Model TT truck drive shaft. One end is an early drive shaft that came off a Model TT rear end. The early rear end in one from 1918 rear end that has the bead on both side of the housing, the rivet that holds the brake plate on and the back upper cover for the worm gear that has NO oil filler hole. Also, on the upper top backside of the housing there is the stamped matching numbers on that rear end that is 18592, so it is early of the 40,000 or so, that were made in 1918. The other drive shaft came off a later, more common rear end. Nothing special here.

As you noticed the splines on the early drive shaft splined end and coupling are both shallow as compared the later drive shaft. That is something to be noticed if you are getting parts to rebuild your Model TT truck. You maybe disappointed if you got the wrong drive shaft.


EARLY DRIVE SHAFT IS ON TOP in both pictures

EARLY DRIVE SHAFT COUPLING IS ON THE RIGHT in both pictures

[HPetrino]

[Steven,

I have a few comments/questions:

1. I didn't know there was any difference in the TT drive shaft from 1918 through 1927. My '18 TT has the beaded clamshell housings and it's equipped with the differential shaft and 2 differential pinion gears. The "later" TT's had a differential spider and 4 differential pinion gears. Could it be that the drive shaft change and the change to a 4 gear pinion set-up were done at the same time? According to the parts book the spider was for 1923-27 trucks.

2. Just for the record the TT1 Parts Book shows only one drive shaft for 1918-1927. Of course this isn't the only inconsistency in the book.

3. Over the years I have asked a few times on this forum about serialized rear end clamshells. Mine (photo below) is stamped 6315 on each half. What can yo tell me about these numbers? So far I have found no one, until your post, who even knew there were such numbers, much less offer any information on them.

Thanks for any further information!!!

[RajoRacer]

There is an article in the Ford Service Bulletins regarding the TT d.s. coupler.

[StevenS]

Henry, I do not have any documented information on the different drive shafts or coupler. Just what I have read on the MTFCA forums and the observations of the 8 TT rear ends I have taken apart (4 standard and 4 Ruckstell). It looks like there is some here.

There is an article in the Ford Service Bulletins regarding the TT d.s. coupler.

As for the numbers that are stamped on both halves on the top of the rear end, there are a couple of comments about them on the MTFCA forums. But what I have seen and read all those numbers are stamped and different on each early rear end. Some of the comments have theorized those are serial numbers. I would agree that is the best guess until somebody can come up with some documentation to explain it.

[HPetrino]

Thanks for the reply Steven. I suppose there are some secrets these old girls are just not going to give up. I've read most of the posts on this forum about TT rear ends, including the discussions about the numbers on the clamshells. My theory is that Ford began production of the TT intending to serialize the trucks via the rear ends but soon decided engine numbers were enough and a separate numbering system for TT's wasn't worth the effort.

Anyhow, my $0.02 worth.