Well, since my torque converter question seems to have stumped everyone, here is a new question.

Today I picked up the transmission Eric W. was kind enough to give me for my brother's van (thanks Eric!) and I need to identify the year of the transmission so I can order a rebuild kit and new torque converter. Here are the numbers stamped on the side of the pan mount:
PK3681861 4766 5812

Cast on either side of the main transmission housing is "104-2".

It looks like this might actually be a lock-up unit since it has two different sets of input shaft splines.

Can anyone tell me the year of this 727 tranny? Thanks!

All 904 - 727 auto trannies have "two sets of splines" where the converter slips-in, the smaller inner shaft is the input shaft.
Look for a through hole going through the middle of the input shaft, that tells you it is a lock-up trans.
DD

Thanks Doc! I actually pulled the pan this morning and saw that the date code on several of the pieces was 74, so it looks like this came out of a 74 or 75 dodge truck.

The pan looked clean and the little fluid that was in there looked nice and red. However, on the filter and on the bottom of the pan was this little collection of bits of hard yellow plastic. At this point I am suspecting that at some point the speedo gear disintegrated, but does anyone else know what part in the transmission is made of yellow plastic besides the speedo gear?

Thanks!