The Stovebolt Site Forums The Shop Area Driveline 47-53 front @ rear axle swap to 1/2 ton

Anyone have experience with this swap? anyone have link to the strings here that are probably out there already that i can't find :-)

Thanks Guys

Jody

sorry 3600 (3/4ton) to 1/2 ton swap. I am swapping the 3/4 ton axles on my 3600 to 1/2 ton axles I purchased. Sorry to the purists but my wife would like to drive the truck and it's just to dangerous :-/

Because the 1/2 ton truck rear axle used a Torque Tube Axle, .
and I believe the 3/4 ton truck is longer than the 1/2 ton truck.
You would have to use a Non-Torque Tube Axle and flipping the 1/2 ton springs.

If the 3/4 ton truck is the same length as the 1/2 ton truck, all you would have to do is find a tranny with a torque tube tail housing.
You should be able to disconnect the 1/2 ton leaf springs at the frame and reconnect them onto the 3/4 ton truck frame.

What year make model are the trucks you have?

Jody, just curious why you think the 3/4 ton axle is less safe than the 1/2 ton. The 3/4 ton has larger brakes, which I always viewed as a safety advantage.

Others can correct me, but I'm pretty sure that your AD 3600 would have a split driveline with a torque tube on the front to the carrier bearing and an open driveshaft to the back connecting to the Eaton HO52 rear end.

That is good news when it comes to changing rear ends. You won't have to mess with the torque tube. You would want a 1955.1 or later 3100 rear end because it is would be set up for an open driveshaft. 1954 and earlier 3100's had a torque tube. You might also find that any year 3200 might fit (guessing here) because the two piece drive line probably had a torque tube on the front and an open driveshaft on the rear similar to your 3600.

Installation should be fairly easy and your existing rear driveshaft might even work. The ujoints might be a different size in the in the 1/2 ton rear end than what fit on your original Eaton, but if so you should be able to find 'combo' ujoints that match to your original driveshaft and your new rear end. You just need to get the stock specs off of both and order a ujoint that has one side that fits the driveshaft and one side that fits the differential.

If the 1/2 ton rear end that you have is set up for a torque tube, it will be a big project to convert and install it.

Send me a PM if you need a 1/2 ton rear end set up for an open driveshaft.

Matt

"You might also find that any year 3200 might fit (guessing here) because the two piece drive line probably had a torque tube on the front and an open driveshaft on the rear similar to your 3600."

There were no 47-55st Advance-Design 3200 Chevrolet trucks.

GMC had a 3200-equivalent New Design (47-55) pick-up.

Tim, good catch...thanks.

Is this what is a GMC had a 3200-equivalent New Design (47-55) pick-up drive line.

Yes, that is the GMC series 102 "3200-equivalent" long-bed enclosed-drive-shafts driveline (102's 125.25" driveline vs the 100's 116" driveline). It was available during GMC New Design years (47-55).

http://www.oldgmctrucks.com/page0010.html

As posted above, "There were no 47-55st Advance-Design "3200-equivalent" Chevrolet trucks."

Therefore, the term "long bed" is meaningful for GMC New Design trucks, but there were no "long bed" Advance-Design trucks.

Thank You Kindly Tim,

wow thats great stuff everyone! - THANKS

Jody

my head is spinning and have to admit I'm a little lost :-)

If I am reading everyones posts correctly; the 1/2 ton torque tube rear axle I purchased will be useless to me and my 3600 that does in fact have the "torque tube on the front and an open driveshaft on the rear". Any options for me here? will changing rear end or trans help make the torque tube 1/2 ton rear axle work for me?

THIS SITE IS OUTSTANDING - really glad I'm a part of it

Jody

Maybellene, thanks for your note. I only think it safer as you can actually buy parts for the 1/2 ton axle. The last time I looked, and asked questions here, there were no outlets for buying the 3600 - 3/4 ton rear axle drums. Would be really cool if I was wrong on that note :-)

Thanks again

Jody

Maybellene,

So If Im reading this correctly you think I can put a 55 or later 3100 rear end will fit into the 1/2 ton torque tube axle?

Thanks again

Jody

Jody, you should be able to find brake drums and shoes for the 3/4 ton, but they aren't as easy to find as the 1/2 tons. The master cylinder is the same on either truck and I think the wheel cylinders are also the same, so parts are easily available. The only real issue with the Eaton rear end is that the tallest gears you will be able to find for it are 4.10's. Other than that, it is a great rear end.

To your second question--So If Im reading this correctly you think I can put a 55 or later 3100 rear end will fit into the 1/2 ton torque tube axle?

Nope, that's not what I'm saying. Sorry to be unclear. Forget about using a torque tube rear end because your 3/4 ton doesn't have one. So you don't want to use a '54 or earlier 1/2 ton rear end. Look for a 1955 or later 1/2 ton rear end and it should fit your rear OPEN driveshaft. The front section of the drive line has a torque tube, but you can forget about that and leave it alone. All you have to worry about is the rear section, the open driveshaft.

All 1/2 tons have a single piece driveshaft, either a torque tube version ('54 and earlier) or an open version ('55 and later). All 3/4 tons have a two piece driveshaft. '54 and earlier had a torque tube on the front section. '55 and later had an open driveshaft on the front section. That part doesn't matter...the key for you is that ALL had an open driveshaft on the rear section, so every 3/4 ton rear end connects to an open driveshaft. That's why you need a rear end set up for an open driveshaft, not one with a torque tube.

Hope this isn't clear as mud!

Matt

Thanks Matt - thats great stuff - THANKS

I really appreciate you taking the time to explain in detail - very kind of you :-)

Thanks again
Jody

Matt,

The 3/4 ton drums available are for post 1950 I think I do know they do not work for the 3/4 ton 49

Thanks for all of your help

Jody