The Unicorn; Or M37 broken long side axle shafts

[IGALL1]

I have a 1960 M37 that I bought when I was 16. I drove the @@@t out of it on my crawfish farm every day for years. Climb levees, running over trees, mudding, pulling fallen trees, uprooting trees, pulling trucks out of the mud, fording, crawling over things that shouldn't be crawled over and every other type of abuse you can think of..... That thing was famous in high school! It is bone stock and I love it. One day I was jerking chicken trees an willow trees out of the ground for fun and I got over confident... I hooked up to a hackberry tree about 20" in diameter and popped clutch! Hit it three times and it didn't budge. My buddy was with me egging me on so I backed all the way up to the tree and caught 2nd gear before the chain tightened. We both got whiplashed into the windshield and my buddy's head spider webbed the passenger windshield pane. At the same time I heard a loud PING come from the rear end. I unhooked, drove to the road pulled it into 2wd high and stomped it....and started rolling backward! I limped it in 4 low to the shop and soon realized the long rear axle was shattered! I pulled out 4 pieces and couldn't get the final stub out because it was jammed in the chunk. I also could't get the chunk out because the stub was locking it in. Here is the tip I figured out: I got my stick welder and found a piece of 1" flatbar and used the last inch of about ten welding rods to weld the flatbar deep inside the tube to the stub. I then welded another piece of flatbar to the end of the piece sticking out of the tube at a right angle. Then I hammered the broken piece out! It worked great!
So it took slot of torture to break mine. Maybe the metallurgy is inconsistent? Who knows. Good information on aftermarket replacements!

 

[Oldfart]

The M37b1's are reported to have some metal differences in the body sheet metal formulations from earlier models. This assertion was due to the later trucks getting rusty quicker. Who know for sure, it might have been due to a different paint primer. In any case, the M37 had a long production cycle with a pause in the middle, so there is plenty of opportunity for variation.

 

[jollyroger]

So here's what I'm doing to "solve" the breakage problem until I can get some alloy axles made. What a PITA to get the case apart. Once you know how to do it, it still sucked. Ha Ha.

I really like how the truck drives with the rear end Lincoln Locked up. It's a beast with the 327 Chevy. I have a couple of lock rights but I think I will Lincoln Lock the rear and lock right the front if I want to fully lock a truck. But then we are talking the need for power steering or full hydro steering.

 

[jollyroger]

I forgot. I called Foote Axles out in California last week. They have a current part number for the rear axles. But they do not stock the part anymore. They can manufacture them. But a single, "sample" set would cost about $2,000. It is a big number because of the setup cost to manufacture the axles. The last time I checked I can have some billet forged steel axles made here in town from Mark Williams for about $900.

But for those prices I have been flirting with getting a lathe big enough to turn axles. Then I would just have to get the splines cut.

The cost per axle from Foote would be greatly reduced if I could get 10 or 20 sets made. That way it would be a production run rather than a sample piece.

And Foote can make the axles out of whatever type of material I want. 1541H, 4140, 4340, Chrome Moly.

We have 5 M37/M43's in the fleet now but they all don't need alloy axle shafts. So until we figure out what we are gonna do I'm Lincoln Lockin' it.

 

[keyslammer]

All,
I'm hoping that some of you might still have your busted long-side axles kicking around. I am looking for a couple stubs for my M37. I plan to pull the axles and put in the stubs for a towing application. I only need about 6" of the hub side axle to be there to slip through the oil seals.