The Stovebolt Site Forums The Shop Area Engine Shop 3/4 or 1 ton ?

Regarding a 41-46 Chevy truck.
Is there a difference in the driveline between a 3/4 and 1 ton?
The truck I'm looking at has a closed driveline off the transmission to a carrier bearing where it changes to an open driveline to a heavy duty rear end.
The master cylinder is mounted off the frame.
Is that enough information to determine 3/4 or 1 ton?

If 41-46 are like the 47-54's the 1 ton has 2 open drive shafts.

mothertrucker
I need more edjucatin. What is the difference between open and closed drive shaft.

My 2 drive shafts on my 1 ton seam to be closed tubes and the front one has what I would call a sliding spline.

Open drive line - you can see the drive shaft spin and U joints are all visible. Closed drive line - the driveshaft is encased inside a tube and you can not see any of it or the U-joints at all.

I know AD trucks thru 54 (1/2-ton) and 53 (3/4-ton) had transmission tail piece with 4-bolt flange. Bolted to that was a mating flange with a ball shaped housing on the end of the driveshaft tube that covers the front u-joint. 3/4-tons had a 2-piece driveshaft, front shaft was enclosed (torque-tube) back to a carrier bearing. The rear shaft was open. By 48 the 1-tons had 2 open driveshafts and no torque-tube, like big trucks. I don't know about earlier. Hope it helps.

My 1941 3/4 ton has open/closed driveshaft. Here's a pic showing the carrier and both sides. I can look at my shop manual tonight as to the differences between the 3/4 and 1 ton. I know the frame is the same style but may be longer on the 1 ton.

[img]http://www.chromeplated.com/photos/B2867E26-0878-4807-92B7-B4E18378CD65.jpg[/img]

41ChevyTrucker, thank you. That's the same driveline set-up on this truck. Thanks for posting the picture. How about your master cylinder? Is it mounted off the transmission or off of the frame?

no problem. dang I am seeing alot of washington folks on this board!

I took a lot of pics when I first brought my truck home here is one showing the master cylinder

[img]http://www.chromeplated.com/photos/6FA7B389-4F1B-4F4F-83E5-AE855B961251.jpg[/img]

This is great. I learned something about the 41-46's here. Thanks

according to the 1941 shop manual here are the models:

1/2 ton
3/4 ton
3/4 ton special
3/4 ton long wheelbase
1 1/2 ton 134.5" wheelbase
1 1/2 ton 160" wheelbase
1 1/2 ton 195.25" wheelbase
COE

The 3/4 ton long wheelbase frame is the same as the 1 1/2 ton 134.5" wheelbase with the exception of a slight difference in the brake cross shaft bracket (not sure what that means). Both have 5 cross members. Master cylinder looks to be the same on the 3/4 and 1 1/2 ton.

Thanks again 41ChevyTrucker for posting the pictures. The master cylinder and clutch/brake pedal assembly is the same on this truck.
I didn't realize that Chevrolet didn't specify a 1 ton truck for 1941-42. I have the same information, however, the 46 Chevrolet truck data book has a model group 3100 (1/2ton) group 3600 (3/4ton) group 3800 (1ton) group 4100 (1 1/2ton).
General Motors of Canada also lists a 1 ton, different group/model #'s of course.
41CT, do you have a picture of the rear end/springs on your truck. I love to see the pictures and the rear end/springs may be a better indication of max gross veh weight (3/4 or 1 ton)
Thanks MT FP OCK F5 for the comments.

maybe a sales brochure might have more details? The guy who sold mine to me said it was a 1/2 ton. I didn't figure it out until I posted these same pics to roddingroundtable board and then I bought the manual.

[img]http://www.chromeplated.com/ericstruck/images/IMG_0040.jpg[/img]

Thanks 41CT
The truck in question is not immediately available for comparison. My rear end/springs may be a little more stout. Thanks for your help. If you need a part, or information, ask, I may be able to help. Best wishes for a Merry Christmas and a Happy New Year.

I'm new to the forum and have just started on a 41 Chevy 3/4 Ton. I see in 41Chevytrucker's picture, the brake return spring is connected to the transmission. Is this the correct place. PO of my truck has replaced the spring with what looks like a clutch spring and connected it from the pedal to one of the rear floor mounting holes. I'm sure this is the wrong place but don't see evidence of any other mounting places

Thanks

Me too....

What is the reason for a closed drive shaft? Reliability? And are they are harder to work on?

The enclosed drive-line keeps the guys at work wondering why all those over-size zip-ties they put on your drive-line didn`t make any noise when you drove off :p
They are more difficult to work on and inspect for wear and such but they have pretty well shown their reliability for many years