5 ton air lockers?

Ajax MD

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I don't have any experience to answer your good questions, but I imagine they must be fairly tolerable, since they were supposedly standard equipment in Marine issued M939's?

I do have 2 used Detroit Locker 5t diffs that I would consider selling.

The air locking fire truck axles are cool, wrong ratio, rare, expensive, and nobody has really thrown any under a 5 ton mil truck yet that I know of. Not even sure if the width and mounting is compatible, such as the torque rod arm mounting provisions. Air brake adaptation should be straight forward for M939's? Same with adding CTIS if for an A2? TBD, none of it has been done that has been posted. I'd love to do it, especially in the front, but don't want to lay out the cash to then only find out it won't bolt up, or is too narrow, or etc.....

Have you tested your traction off road yet? You can get these truck stuck pretty good without any type of traction assisting diff.
I haven't taken my 5t off road yet but I've seen what can happen. Lots of SS videos of Haspin and Rausch Creek online of some big-time quagmire. I don't have a winch.
Just once or twice, I want to attend the Rausch Creek rally. It's a bit of a haul for me down here in Annapolis.
I'll bet shipping costs of your Detroits from Michigan would be ugly. :)

This fall/winter, I hope to finish up the routine, deferred maintenance and then I can focus on fun stuff like lockers, paint, canvas, etc.
 

74M35A2

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Understood. A winch probably adds more value to your truck than lockers, on a cost basis. If it is mostly just for attending a rally, then there will be a lot of other trucks there cheering you on to get stuck, get out, and would help pull your truck out if need be.
 

Jbulach

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I've read this thread from start to finish and I have a few questions.

I've owned 4x4's in the past, but never had a locker. I understand the difference between an air or electrically actuated locker and an "overrun" locker like Detroit or Cannonball.
What I don't exactly understand is, what happens or what are the handling characteristics of an overrun locker when driven on pavement, especially in a 6x6?

Is the handling squirrley during straight-line driving?
How bad is it during turns in on-pavement driving? What happens?
Do overrun lockers really eat the tires much more quickly in on-pavement driving?
Is a locker in just one rear axle a pointless exercise or does it offer some assistance?
On an M813, I assume installation would require removing the bed?

I'm not trying to build an unstoppable machine, I just want a little occasional advantage. I'm thinking either an overrun locker in the intermediate axle or both rear axles if the money presents itself. I won't put one in the steering axle. I don't want the complexities of additional air lines or electronic actuators, just the simplicity of automatic, mechanical engagement. My on-pavement driving is pretty much straight line and not really any winding, mountain road type of stuff.

If lockers cause a lot of unwanted stresses on axles and other components, I'll just leave things alone.
Be careful, a cannonball like Red barn sells is not a locker, it’s a spool, and can be very hard on things if you haul weight or run on the road much. Sounds like a Detroit would be fine with your typical driving. I think just the intermediate axle would help tremendously in serious twisty situations when slick. Although I would suggest going off road first, I think you’ll be shocked at where these trucks will go, unless it’s muddy! Then your best bet is to drop the tire pressure down to about 10psi and hope it stays on top.
Not saying you cant put the intermediate in full drop and snake it out but I would pull the bed.
I agree with a winch first though, big electric on a double receiver mount so you could move it to the rear if necessary would be nice.
 
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Ajax MD

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Be careful, a cannonball like Red barn sells is not a locker, it’s a spool, and can be very hard on things if you haul weight or run on the road much. Sounds like a Detroit would be fine with your typical driving. I think just the intermediate axle would help tremendously in serious twisty situations when slick. Although I would suggest going off road first, I think you’ll be shocked at where these trucks will go, unless it’s muddy! Then your best bet is to drop the tire pressure down to about 10psi and hope it stays on top.
Not saying you cant put the intermediate in full drop and snake it out but I would pull the bed.
I agree with a winch first though, big electric on a double receiver mount so you could move it to the rear if necessary would be nice.
Thanks for that. Ok, I'll steer clear of the cannonball and opt for Detroits if I decide to install locker(s).

A winch is good, but winches are for getting un-stuck. Lockers prevent you from getting stuck in the first place. ;) Still, your point is taken and I will investigate some of the larger electric winches out there.
 
So far the trucks I installed detroits in the owners said they don't affect street driving. I've ran the airlocker 7tons in my mud trucks for years and am in the process of freshening a set up and putting airbrakes on them to put in a M936. The housings are the same width as a regular 5ton you just have to cut all thebrackets and crap off so you can bolt the 5ton brackets on them. Ctis is a bit difficult to make work with the rear airlocker axles because the spindles are part of the axle. Though I have a few ideas that I plan to try when I install them in my M932A2 later on. The set for the m936 will using the 5.81 headsets with 395 super singles and he is swapping in a tuned 350 small cam so the truck should roll along pretty good when finished and the intermediate axle has a power divider so that will relieve some drag too.
 
If you plan to wheel much a winch will be a must. And lockers help prevent getting stuck but a wise old man once said 3 wheel drive will get you where you want to go and true 4wheel drive will get you in trouble. Lol same goes for true 6x6. You will get stuck eventually and it will be stuck worse than if you didn't have lockers. Lol At that point just be sure to have a winch or back up with you.
 

Ajax MD

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If you plan to wheel much a winch will be a must. And lockers help prevent getting stuck but a wise old man once said 3 wheel drive will get you where you want to go and true 4wheel drive will get you in trouble. Lol same goes for true 6x6. You will get stuck eventually and it will be stuck worse than if you didn't have lockers. Lol At that point just be sure to have a winch or back up with you.
I don't disagree but I won't be wheeling often or very hard. I'll look into winch options.
 
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