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Anyone swapped a set of pre 93 Dodge 3/4 ton or 1 ton axles under their M37? Once my disel swap is complete, I would really like to make my M37 a daily driver. I figured swapping out axles for later model ones would be a cheap way to get disc brakes and streetable gearing.

The biggest downside I forsee is the steering. Any opinions?

With enough time, money, and engineering know-how, any modification is possible. The swap you mention shouldn't be terribly difficult to accomplish, but your newer axles will be wider than stock and the stamped steel wheels from a 3/4 ton just wouldn't look "right" on an M37.

I plan on running stock HUMVEE rims and tires on it, and I beleive they look pretty good on the M37. Your opinion my vary.....

No one else had any input? Surely this has been tried before?

From an esthetic point of view, modern axles are too wide. Wheels look good but too much tires out of the fenders.
You have to check your State regulations to see if it's street legal.

HUMVEE rims have over 7 inches of backspacing versus the normal 3.5 to four on most tims. So I can fake an extra 7 inches of axle width hidden behind the wheel and it won't stick out any farther. And Texas has no covered wheel law like some other states.

I guess I need to do my homework and figure the WMS for the stock M37 axle and the later model varients.

Thanks for the input so far.

WMS?

Wheel Mounting Surface

I put a dana 60 front, and a 14 bolt gm in the rear 4.56 pos both ends. I have a machine shop so it was no big deal to cut the housing and axels down to fit, BUT DO NOT MATCH THE OLD WHEEL BASE MAKE THE AXELS 2 INCH WIDER!!!! I did not and boy did I pay for that mistake...Phil in Mt

you mean, oh, like... this??



sorry, thats the only picture I have here...

those are mine. Yanked them from a 78 dodge snow commander. Too bad the rest of the truck was trashed, as it was originally a 440 4 barrel 727/205 truck.... Mine have a 4.10:1 with a limited slip in the rear.

Rear will bolt right in. Literally. The stock axle tubes are 3 1/2" in diameter, D60's are 3", so I cut a chunk of I think it was 3" Schd. 80 pipe in half and then welded them to the axle tubes to increase the diameter, then used all the stock hardware to bolt it in, including the spring plates, and the struts.

Front is a bit trickier. The D60 has the axle pad cast into the pumpkin, so The passengers side spring has to be relocated OUTSIDE the frame, instead of under it. I ground the rivets out of the original front spring mount, then cut a 2" thick block if steel and welded it to the stock mount, then welded a plate under that, butted against the side of the bottom of the original spring mount. This plate extends all the way under the frame rail. I then bolted it with grade 8 hardware through where the original mount was riveted.

For the rear mount in the front, I welded a vertical gusset to the side of the frame rail, and then welded a piece of thick tubing with the same internal diameter as the spring shackle bolt to the bottom of the gusset, at a 90* angle to the side of the frame. this tube is spaced off of the frame side enough to allow the inside shackle arm to fit between the fram, and the tube. Then, the stock bolt is passed through the outer shackle, the tube, then the inner shackle. All done.

The drivers side mount I ground the pad off of the axle tube, and relocated it to fit the original spring.

You'll have a ferocious driveshaft angle, and will most likely have to move the transfer case. I moved my case over to the drivers side as far as I could before it almost hit something, then redrilled holes in the cross braces, and bolted it back down. I think I moved it about an 1", if I remember right (this was almost 7 years ago...). This 1" doesnt seem like much, but its enough to kill the vibration that will happen if you don't. Try yours first, and see what you get...

D60's are easily the best mod I ever did to the truck. the stock axles were like a bad best friend... Always costing money but they never really ever pay you back.

The heavy duty disc brakes on mine work great with the stock manual master, and the rear drums do ok.

Oh, one more thing. My front axle is not in line with the rear. It is 1/2" to the passengers side, but unfortunately, there isn't much you can do about it, as a result of the spring situation. My truck always tracked straight, and never pulled though, because I used all of the factory holes in the fram for spring mount locations.

EDIT:

Steering: I took the original steering knuckle arm to a machine shop, and had them heat and press the ball stud out of the arm (its silver soldered in) then I drilled the Dana arm for the larger stud from the M axle, pressed it in, and welded it at the bottom. Done. Side effect is that the D60 arm is about 2" shorter. Steering effort is a little higher, but the payoff is a turning radius about 10 ft smaller, as the steering box still travels the same distance, but the shorter arm carves a steeper angle as a result.

EDIT 2: See the orange thing in the pic? Thats a steering stabilizer. If you dont have one, get one. For some reason, the D60s are more prone to "the death wobble" then the stock axles.

I am still working on my dana 60 Swap. Here is what I have done.

got a set of Dana 60's from an '83 dodge truck

FRONT:
Remove the front and rear spring mounts. Fabed up my own front mounts resembaling the original fronts so they bolt in. I will try to post my drawings later. I took the original springs to a spring shop and had them make a set that make me a set that are 2.5" wide (like the '83 dodge) that could hold an additional 400lbs (added weight of cummins and winch). I removed the shackle bracket from the '83 frame. I made some 13/16" high 1 1/4" diamater spacers. I mounted the bracket to the outside the frame with the spacers.

REAR(plan):
I cut off the original spring mounts on the dana 60. I have ordered some 2" spring perches and will mounted them on the dand 60 so I could use the orginal springs.

Josh wrote: EDIT 2: See the orange thing in the pic? Thats a steering stabilizer. If you dont have one, get one. For some reason, the D60s are more prone to "the death wobble" then the stock axles.

Isn't one cure, for death wobble in a king pin axle, adding shims to the lower spring to make it stiffer?

"Death wobble?" What's that? I grew up in an era when most cars and all trucks had straight axles with kingpins at each end. Independent suspension was only available on the "new" cars that us high school kids couldn't afford. I learned all about "bump steer" from them, but never heard of a "death wobble."

Death Wobble is a condition where the front steering violently cycles/shakes back and forth uncontrollably...usually resulting in loss of control if not stopped. Typically affects lifted trucks with modified suspensions and larger tires...Dodge trucks (1994+) are notably the worse for this condition and the source for the term "death wobble"

In the king pin axles, it is typically cured by placing spacers or heavier springs in the bottom kingpin to add more preload...

The steering stabilizer is typically thought of as a band-aid to the actual cause, and typically not recommended...

I see! If ever there were a valid reason not to modify a vehicle, that would the leading contender! While some modification might be done without exceeding the limits of the designed-in safety factor, it might be prudent to obtain a degree in mechanical engineering before attempting any modification.

I think the issue with mine is that the stock springs have rotated the axle a bit, causing a few degrees of caster, so it steers like a road grader on some level. the only way to truly fix it is to cut the tubes and rotate the knuckles... but, Im not doing that for a 1.5* of caster.

The other thing that will cause it is a worn or loose steering system, kinda like what we have, where you can turn the wheel 1/8-1/4 turn and not hit anything...

EDIT:

The death wobble I get could also be a function of the shorter steering knuckle arm overcoming the resistance of the stock steering box as well.