3/4 ton axle conversion/ 1/2 Ton axle conversion

[hotcorner216]

I have an 86 m1009, I've been also thinking of getting a 70-72 C10 (2wd)....I know someone selling a 72 C20 4x4 with 3/4 4x4 axles, would it be feasible to convert the C20 3/4 ton axles to the m1009 and the 1/2 axles to the c20 and make it a 2x4? I know I could just find a 2x4 but the price and condition of this c20 are hard to beat and it has the axles I want for the m1009 so itd be a double win.
Thanks

 

[Skinny]

What is your end gain by trying to do this? Anything is possible but going to 3/4 ton really isn't giving you a big upgrade at all. It is also going to make you rework the truck around 8 lug axles without much strength increase. What gearing is in them? Are they original?

If you are going for strength in order to go up to bigger tires, you probably will spend your money wiser on a set of M1008 axles and get the gearing and locker to go with it. A 3/4 ton front axle is like lipstick on a pig.

 

[Recovry4x4]

For someone tooling around on the street, the 3/4 ton stuff is ideal. The 10 bolt rear is the achilles heel of the M1009 so the addition of a full float rear is a huge step up. The 72 4x4 will likely have a 60 in the back. Memory says they also have a narrower spring perch width. Larger front rotors add some braking power but you gain no actual strength in the front.

 

[FMJ]

I have an 86 m1009, I've been also thinking of getting a 70-72 C10 (2wd)....I know someone selling a 72 C20 4x4 with 3/4 4x4 axles, would it be feasible to convert the C20 3/4 ton axles to the m1009 and the 1/2 axles to the c20 and make it a 2x4? I know I could just find a 2x4 but the price and condition of this c20 are hard to beat and it has the axles I want for the m1009 so itd be a double win.
Thanks

Your logic is sound, I did the same thing to my 86 1009. I found a 14 bolt rear with 3:73 gears and a Dana 44 front with 3:73 gears. Could not be happier with the conversion. And like Kenny said, unless your doing serious wheeling, especially with a 1009, you don't need a 60 up front. If it's a 6.2 or even a 6.2 with turbo, you going to have to really work hard (be stupid) to break the front axle.

http://www.steelsoldiers.com/showthread.php?28401-New-Axles/page2

 

[Skinny]

OP has yet to define what he wants to do with it. So far all we know is that he wants to install older axles without any specs or reasoning behind it.

 

[chevyguy1976]

It could be done but you would be better off with a 81 or newer 3/4 set up, spring perches, transfer cases ect... That 1972 stuff is a little different. A 72 3/4 would be worth more as a collector truck then a chopped up 2 wheel drive.

 

[nyoffroad]

You'll find that the rear spring perches are located in slightly different location. Years ago I did something like this, I picked up a real nice 'short bed' pick up at auction. It was a stolen and recovered but it was actually a modified Blazer frame with a PU cab and a shortened bed on it. (COOL TRUCK) Unfortunately the thief stole the drivetrain, I had an old (1972) rusted out Suburban with good matching 3/4 ton axles. I did the swap but had to cut the perches off and reweld them. It wasn't hard to do but if I was to do it again I'd but new perches from Summit (IIRC) and do it with the axle clamped in place with the U bolts instead of on the welding table. I don't remember any problem with the front axle

OH YEAH!! shock mounts need to be changed/rewelded, I don't remember how.
The rear u-joint will be different size also, that can be overcome with a 'conversion' joint available at any good drive shaft shop.

 

[FMJ]

U-joint is precision 447

http://www.summitracing.com/parts/PCN-447/

 

[Bob H]

a 72 3/4 ton 4x4 is kinda rare around these parts.
I'm missing something here, end result of the 72 being a 4x2 ????????????

I have been considering swapping my M1009 axles with a set with 3.42 gears out of a 87 1500 PU

 

[Skinny]

Wait! So we are completely guessing on what parts are installed on a 45 year old truck axle? Sure, it could be completely bone stock. It also could have been gutted and rebuilt internally, mounts reworked, newer axle housing installed in older 72' truck, yokes replaced, different sized joints installed, etc. etc. etc.

These things are nearly half a century old and we are guestimating over the internet without any specs, measurements, or photos to go off of. Freakin' truck could have an Eaton rearend swapped into it for all we know. I think there is some good strategy here but I will play devils advocate and say all the speculation is doing the OP no favors until more information is available on the donor and OP's intentions with the CUCV.

My II cents...

 

[cucvrus]

I know this don't pertain completely to this thread but I want to put it out there. I had a 1969 K30 pickup. It was an airport plow truck. It had Marmon Herrington axles under it. They were not factory but the front axle had wet outer knuckles and the differential cover was bigger round then the 14 bolt rear axle in a CUCV. The rear axle was about the same size. That was 35 years ago and a man bought the truck to mount a log loading picker on it. It just sat up stationary and had out riggers and a claw to load logs onto trailers in north east PA. The truck was 2WD when it left the factory. And I think it had 513 gears in it. Posi front and rear. 292 straight 6 GM gas engine 4 speed divorced transfer case and would climb a mountain at idle. Low range would pull a house down. It was sold a auction for $900. when I bought it and ate gas like water. I sold it for $1500. about a year later. That had real HD axles under it. I don't know anything else about it but it had Marmon Herrington stickers on the dash that explained the transfer case and the lockouts. Tough truck. I wish I still had it. It was baby blue. That is the same company that made 1/2 tracks in WWII.

 

[rsh4364]

Hind sight is 20/20,I still think about the numbers matching 69 Z-28 I passed on when I was 18,original paint too,I said no because it had spun a rod bearing..He wanted 1,800$..Who knew?