Why the Deuce Doesn't Have These I'll Never Know!

One thing that always has amazed me about the M35 series trucks are the lack of locking differentials in both the axles and the transfer case. It seems to me that if you going to design a truck for serious off road work you want to make sure that power is even distributed between the front and rear axles as well as between the left and right side of the truck itself. The seems to be no reason to have a truck designed to operate 80% of the time off road or on roads that are barely road like in any sense of the word and not give the truck as much traction as possible.

So here is my plan to install an Oshkosh 55000 series Transfer case in the truck. One with 2.16 low range and .98 high range. Then I want to couple this to a new Fuller 6sp Medium duty transmission. The 55000 series transfer case has an air-locking differential gear in it and if you get the right type you have this with an air-disconnect front axle. I think that is a must. That way the truck basically has all the same features as the original transfer case but with one important addition locking differential in the system. That way I have 50/50 power when needed. Also couple this to air-locking diffs from ARB and a new IH DT466 200+hp engine I think the truck will be unstoppable.

Obviously the low range of the new transfer case is really low there is major increase in low range which might cause axle damages... But i figure I'll have to upgrade the axles shafts anyway. So what sort of axle shafts do the monster truck guys use in the 2.5ton axles? And I know know the propeller shafts will need to be upgraded but hey that shouldn't be a problem. I figure the Dana 1710 series shafts should the trick.

My big problem is money. I would love to do this tomorrow, but I fear it will have to wait...

So do you guys think they're any problems I'm not looking into? Perhaps increasing the supports on the front and rear suspension? I want to also add torsion bars to the other side of the axles on the rears. You know sort of round out the look and balance out the truck. i figure with the extra torque the mounts and torsion bars might be handy in deep mud and stuff to keep the axles from laterally moving too much.

So that is basically my plan... Oh and Heated Seats! Yes, I want to be warm and cozy as do I off roading summer, winter , fall and spring.

the deuce t- case doesn't need a locker. (it is always locked)

The most bang for the buck comes with adding lockers. Better get some better tires too.

I've never read anywhere that the power is a true 50/50 split; and considering how the sprag type unit worked with dividing the power only when the rear wheels slipped that leads me to believe that is not locked at all. I think system is open just like the diffs. Besides the Oshkosh 55000 series takes more torque and has better ratios. Think of the possibilities.

The .98 x.79x6.72 would give you 5.202 final ration which would probably send you up to about 60mph at 2300rpm with 9:00x20's. Now if you have newer Fuller 6sp transmission like want to put in in it: that would .98x.78x6.72 for 5.136 that would get you to 60mph at 2300rpm no problem.

M1075 said:

The most bang for the buck comes with adding lockers. Better get some better tires too.

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Yeah but it is not enough to divide power equally between the left and right if the front is slipping then only the rear is pushing. You need the rear and front to have equal power as well. This is to me is the most important factor of why the Kraz 255b is so impressive, it not only locks the diffs but the transfer case well. Once you go into full locked up mod the truck has equal power between all six wheels no matter what. and you really cannot beat that.

The Oshkosh 55000 is a big sucker and I believe it is a 30/70 split.

Rolling_Eudaimonia said:

Once you go into full locked up mod the truck has equal power between all six wheels no matter what. and you really cannot beat that.

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Unless you have 8x8 or 10x10! Maybe you should step up to a HEMTT or something bigger.

http://www.ouversonengineering.com/axle_products

Those are about the best axle shafts you can get!
And if you want to put in lockers now, but upgrade axle shafts later, then get his locker.
He can make a few mods to it and it will still work with the 2" 47 spline shafts as well.

Rolling_Eudaimonia said:

I've never read anywhere that the power is a true 50/50 split; and considering how the sprag type unit worked with dividing the power only when the rear wheels slipped that leads me to believe that is not locked at all. I think system is open just like the diffs.

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The stock m44 t cases do not have any capacity to "divide" the power. They provide no differential action.
all the sprag does is engage front drive (same with the "air" in the airshift)

BFR said:

The stock m44 t cases do not have any capacity to "divide" the power. They provide no differential action.
all the sprag does is engage front drive (same with the "air" in the airshift)

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Well the sprag only actuates when the rear axles slip. So if the power were equally divided between the front and rear axles of the transfer case then front wheels wouldn be always engaged. The unit would always think the rear is slipping since the power is being equally divided between the front and rear. So I think it uses a limited slip differential in the transfer case unit so that when it spills from the rear it engages the front.

The air unit might be fully locked up, if so great. But I don't think it does, I've watched the front wheels grip and the rears seem to have no power. I think they just added an air disconnect to the unit to give the operator greater control over the truck. I like the air disconnect option myself but I want the case to lock and divide power evenly when I'm getting stuck.

Plus it would be great if the unit could hand 660ft-lbs of torque running through Fuller transmission with a first gear of 7.05 to 1 coupled to the 2.16 of the Oshkosh 55000 transfer case you have mud eating monster.

lockers would be nice, but the tcase is fine

If you can lock up the Transfer Case then I want it on my truck. I want the drive train so locked up that it attempts to move the Earth in the direction I drive.

It's easy to lock the tcase just use the air switch under the dash board.

R.E.: may I suggest studying TM 9-2520-246-34 and -34P to tell us exactly how our transfer cases do work....?

FYI, not the sprag T-136-21 TC, but YES the T-136-27 airshift TC gives you true 100% positive locked equal speed forward/backward 6x6 operation when front axle is engaged! Nothing less compared to a TC from a Graz or the Ural or the M880's NP203 when their internal diff. is locked.

I do aggree though that a TC differential would be a great plus in our trucks if we had to drive most of the time on slippery surfaces.

G.

I'd just throw a detroit in the diff along with the Overson shafts. That is a pretty serious system without the cost and extra work of air lockers. Detroits are positively 100% locked as long as the gas is on, but will unlock when you're coasting so it is easier to turn.

BFR said:

the deuce t- case doesn't need a locker. (it is always locked)

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I don't think so. I looked very closely at the dash switch once and I had a weird feeling when I was driving the truck once and the tires were slipping. I'm sure the t-case does not lock up. Why else would mud boggers use the case? They never drive in the mud so they don't need traction like I do in my MV.
I would appreciate it if you would keep your facts out of my thread and not correct me when I am wrong. If you don't I will be forced to ignore you and keep asking the same questions until I stumble across an answer that I am happy with.

tsmall07 said:

I'd just throw a detroit in the diff along with the Overson shafts. That is a pretty serious system without the cost and extra work of air lockers.

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the ouverson locker is stronger than the Detroit if you want the hardkore stuff

Original question was why the M35 doesn't have lockers as standard equipment: A significant number of these trucks never left the hardtop.... moving materials on and between bases, etc. Some of the more special app. trucks (Marines, etc.) did have lockers installed.

I admire your plan and concur that lockers would improve offroad capability.... But I am curious as to the intended use? I have driven M35's in all kinds of terrains and have been stuck more than once. On occasion, a locker with better tires would have made the difference but the vast majority of the time the truck was stuck because of the weight and/or lack of ability to manuever. Put a loaded deuce on soft, swampy ground....let it sink to the frame and no combination of inter-lock diff....lockers or big ole tires will get you free!!

My main heavy hauler is a Ford L9000 with interlock for the diffs and air lockers for each axle. I NEVER put it in deep mud, soft ground, etc. Use the locking systems to get started on sloppy surfaces or MAYBE climb a slick incline so long as there is no sideways ground. Just too much truck and weight to be a true offroad vehicle. This particular truck has been stuck when my jeep would climb the same road in 2WD drive.

Just food for thought from someone who stuck a truck so badly in November, 1977 that we had to wait for the dry season in June, 1978 to pull it out!

JR

rizzo said:

I don't think so. I looked very closely at the dash switch once and I had a weird feeling when I was driving the truck once and the tires were slipping. I'm sure the t-case does not lock up. Why else would mud boggers use the case? They never drive in the mud so they don't need traction like I do in my MV.
I would appreciate it if you would keep your facts out of my thread and not correct me when I am wrong. If you don't I will be forced to ignore you and keep asking the same questions until I stumble across an answer that I am happy with.

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Rizzo, That's kind of the felling I was getting.
opcorn:

Maybe they left the locking axles off, since they'd be traveling with friends anyway.

Some with winches, and some with tracks and a cannon on top