The Stovebolt Site Forums The Shop Area General Truck Talk 1/2 ton to 3/4 ton--what's the difference?

Hello all--I'm considering purchasing a 72 1/2 ton 4x4 only because I can't find a decent 72 3/4 ton 4x4, (which is what I really want), for a reasonable price. I'm thinking the main difference is the springs. Can I just find a rolling chassis from a 3/4 ton and swap them out? The truck already has a 12 bolt rearend in it. Should I look for a 14 bolt to swap into it or just add stiffer springs. Do I definitely need the 8 lug setup? because I have a 70 3/4 ton parts truck with a 10 bolt spring rearend in it, but am not sure about the strength of the 10 bolt. I want to use the truck for towing my boat and general hauling. Any info or ideas would be appreciated. Thanks, MM

The 3/4 ton has a heavier frame and heavier suspension components. 8 lug axle hubs are needed to maintain the load capacity of the 3/4 ton.

If all you're hauling is a light boat and light loads, you don't have to have the 3/4 ton chassis. If you're wanting a 14 bolt axle, get one from a van that is a semi-floater. It should have six lug drums, but you have to be careful with the wheelbase width.

As Fred said, the Frame is heavier, as are the springs and shocks (and the way they are mounted is slightly different).

The 1/2 ton may not have as beefy an engine, but that's easy enough to swap out.

The rear end is geared differently, and the brakes are usually larger as well.

3/4 tons may have a longer bed... you may want to be careful with that.

Aside from that, you should be okay with a 1/2 ton to 3/4 ton frame swap. There'll be some finagling when you mount the body, but it shouldn't be too bad.

My boat is pretty heavy and I do haul some pretty good size loads at times. Maybe I should consider a frame swap with the 70--even though that rearend is only a 10 bol. I didn't realize the frame size was different between the 1/2 and 3/4 ton. I still need to find an 8 bolt front axle. Is a frame swap a huge undertaking? MM

It depends upon how many helpers you have.

A frame swap would definitely take care of the 6 - 8 lug axle in the front, and you'd have shorter gears in the rear. You can also interchange the carriers between the 3/4 ton and 1 ton differentials, so if 4.55:1 isn't a large enough ratio, you can go and find a 67-72 1 ton carrier (they usually have 5.16:1 gears) and swap them with no problem.

Unless your boat is a Yacht, in which case, I'd start looking at Macks.

(Just out of Curiosity, why are you wanting a rear end with more than 10 bolts? How big IS your boat?)

I was under the impression that the 10 bolt rearends arn't as strong (smaller ring and pinion) and are more inclined to breakage. I want the 4 wheel drive for off road etc. Posi taction in the rear axle is also something I would prefer. Do 10 boltd come with posi? MM

Well, that's true... Ring/Pinion are a bit beefier in the 14 bolt. You'd REALLY have to be mean to the truck to break the diff, though.

Dunno about the Positraction in the 10 bolt diff...

What about doing a frame swap on something newer?

I know the 73 and later frames are longer (at least the wheel base is) Do you know if the body etc for a 72 or earlier would bolt right up or would there be a lot of fabriation mods? MM

Rocket,

Here is what I would do. I would buy the half ton and then swap in the 3/4 ton parts you want/need. This would be the option as long as it is cheaper, it wouldn't make much sense to save money on the half ton and then turn around and spen more making it a 3/4 ton.

As far as parts I would put a full floating (8 lug) 14 bolt in the rear end. This can be sourced from a 73-87 truck. Since it is a rear end it can be a 2wd or 4wd truck that you get the axle from. Make sure to get a gear ratio you want.

In the 73-87 body style there are three eight lug front ends. There is an 8 lug 10 bolt, an 8 lug Dana 44, and an 8 lug Dana 60. If it were me, having owned and operated the 10 bolt, I would go for the Dana 44. The only way that I would use the Dana 60 is if I was planning on building an off-roader. Otherwise it is just overkill.

As long as you get the motor, tranny, and transfer case that you want in the half ton then I see no reason no to swap in the newer axles to increase your towing capabilities. You could take the springs and hardware from the newer truck and just toss it under yours. I know that swaps like this are done all of the time by off road guys, so I would check some off roading magazines and websites to see what they have done. Good Luck.

Kyle