How to determine transmission date codes

[thsmith]

I have looked in my Palmer book but can not find how to determine transmission date codes. Any know how to judge the year of a 4 speed big twin tranny.

Thanks,

Tracy

[Guest]

On the bottom of trans on the kicker side should be a raised boss. On this boss, near the casting part number, should be a letter and a number. The number is the year and the letter is the month.

[thsmith]

If the tranny date code is J9, does this mean the month is October and 9 is 39 or 49 or 59 ? Which one ?

Thanks,

Tracy

[caschnd1]

If you figure out what type of transmission case you have (what year ranges it was manufactured) you will be able to determine if J9 means Oct-1939, Oct-1949, or Oct-1959. You many need to look at the kicker cover for clues too, but that only helps if the kicker cover is the original one. Here is some info I posted on the other forum:

For Big Twin transmissions 1936-1964 there are 4 types of transmissions cases that were used:

Type 1: 1936 - identified by only having the 4 mounting studs holding the transmission to the frame. The 5th mounting hole located under the kick starter does not exist on these transmissions. Additionally, there is no boss for this 5th mounting point cast into the transmission case. I believe a bracket was used between the kicker cover studs and the frame in 1936. Additionally, this case has no vent boss cast into it. The vent boss is normally located on top of the case just forward of center on the kicker side. During these years the transmission vent was located on the kicker cover.

Type 2: 1937-1939 - identified by having no vent boss cast into the transmission case. The vent boss is normally located on top of the case just forward of center on the kicker side. During these years the transmission vent was located on the kicker cover. Five mount points on all cases 1937 and later.

Type 3: 1940-1955 - The transmission vent has now been relocated from the kicker cover to the transmission case. The is a vent boss cast into the top of the case just forward of center on the kicker side. It is drilled and tapped for a vent screw (not one of the screws that holds the transmission top in place).

Type 4: 1956-1964 - The transmission vent boss is still cast into the case (top of case, forward of center on the kicker side) but it is no longer drilled and tapped for a vent screw. The venting is not achieved using one of the screws that secure the transmission top.

[thsmith]

Thanks, this is a great help.

Tracy

[Bananagas]

Can anyone help me identify the year of my 4speed? Thanks in advance for any info.

[Bananagas]

Sorry one more