The Stovebolt Site Forums The Shop Area Driveline 1940 half ton numbers investigation

Hi all - I have a 1940 half ton that has been in the family since the 50's. I have been told by an older brother that the tranny and rear end are not original. I have some numbers but am not sure what info they provide.
The tranny numbers I have are K308. It is a 4 speed. I believed the 1940 came with a 3 speed as standard and the 4 speed as an option. My fellow Stovebolters have told me the 3 speed was a synchronized tranny and the 4 speed was not, and the non-synchronized would require double clutching. This pick up was revived and put on the road for another brother to drive in the mid 70's, and I remember it then. I don't remember the need to double clutch, which makes me think it is a newer tranny than the 1940, like my brother said. Looking for guidance to determine the year, origin and info needed to order any parts for that tranny.
The rear end numbers I have are 3652330. It is a 10 bolt. I was told by my brother that it had been swapped to gain more pulling power. That sounds odd to me because I thought the original 1940, 1/2 ton came standard with 410 gears. Looking for guidance to determine the year, origin and info needed to order any parts for that rear end.

If you use the full editor when posting, you can add pictures. They would help in this case. The K308 is a date code, November 30, 1948, 58, or 68, etc...... Pictures please.

Do you have an open or closed driveshaft?

What type of parking brake do you have...rear drums or back of trans?

We know you have a 1949 235...maybe they swapped in the '49 trans at the same time???

Pictures will help...

Mike B

Thanks Joe - that date code makes sense since I now know (thanks to Mike) that the engine is a 1949, 235 from the 6000 series trucks. Engine date is January of 1949, so the tranny being a mate to that engine is a distinct possibility. The pickup is not disassembled so I don't know how good the pics will be but I will give it a shot.

Mike - the park brake is rear drum. I'm not sure what you mean by open or closed driveshaft. I will try to get pics and post.

It is starting to look like my older brothers recollection was not too far off. He was pretty sure the motor, tranny, and rear end were not original and the date code on M & T being so close, I am guessing we will find the rear end to be the mate to the M & T. I will keep digging and post more pics.

I just looked up the Chevy 6000 series - not very likely the rear end is from a 6000 is it?

Not likely...6000 series would be dual wheel...

Open drive shafts are what we have in our modern vehicles, you can see the shaft turn and the U-joints are exposed. Closed drive shafts are called torque tube rears, the U-joints and drive shaft are inside the tube, you can't see them spinning...looks like a solid pipe running from the transmission to the rear.

Mike B

Mike,

Just updated your Stovebolt Bolt Bucket! Lots of pictures.

After you asked and I went to the shop and looked I felt it was kind of self explanatory. Your description confirms it is a closed drive shaft. Added a few pics. I also discovered some numbers on the driver side of the rear end housing. They appear to be vertical by the attachment screw head castings and I believe them to be either A 8 or 4 8. I lean toward the 48 because I really worked to expose them and just cant convince myself it is an A.