4000 Industrial date codes...mutt?

Here are pics of the date codes I found on the 4000 industrial I looked at today.
Starting up front, I found 4K26 on the engine block. That should be October 26, 1964 if I'm not mistaken. Curious that the serial number calls out a Sept 1964 build date.
The date code on the trans is 3J5 which I take to mean September 5, 1963. But on the same transmission I found a stamped serial number of 58725 which my book claims left the factory a full year after that (see my previous post). Also suspicious is the fact that the transmission is a dirty faded pale yellow while the rest of the castings are a pretty blue.
Moving to the rear, the date code on the left side down by the inspection port is 2G26 or July 2, 1962. Another year (plus) earlier. On the left rear axle I found this:
I don't know what this means. If it were just H54 I would take that to mean August 5 1964, but I don't know what the B or the X mean. Any help?

The other axle code was unreadable. The radiator had a date of 9 64. So I guess my main questions are the goofy axle code and the discrepancy between the serial number and the date code found on the same transmission.

FYI, this tractor does not have any indication of having had an SOS in the past. There is no hole in the lower dash were the sos shifter would have been. It has a shuttle gear to quickly go from forward to reverse in any gear. It does not have a pto or a 3ph. My b-i-l is looking at it seriously for snow removal and other sundry loader chores. Asking price is $2500. What do ya think?

The 2G26 on the transmission housing is a casting number, so that tells you the date that the transmission housing was cast. It was most likely assembled into a finished transmission at least a few months after that, or maybe even longer, and then the tractor was assembled at an even later date.

Hello Jim , All of the date codes except the Engine Block (which could have been a WARRANTY REPLACEMENT back when it was new) are correct for the tractor . 1963's , 1964's , and 1965 tractors dates are all over the place because of the low volume of sales . In 1963 they were building about 100 tractors a month while in 1964 it dropped down to about 60 a month . The B is not part of the date code and the X is for Experimental , very common on 1964's and 1965's . Thanks Tony