deuce transmission disaster...(pics)

[jwaller]

deuce trans disaster...(pics)

I blew this tranny some years ago but just today got around to opening it up.

I thought I'd post up some pics of the carnage for you guys and also add a word of caution for all of you running the lockout hubs on your tandem rears.

All this IMO was caused by driving with the lockout hub incorrectly.

with a very rough road----------------------------
what I realized afterward was that when I was running down the interstate the rear axle in my truck kept bouncing (forward is disconnected) and when it would bounce the motor would wind up and shock load the trans and every part of the driveline.

when the main shaft broke it became out of round and also busted the seal carrier on the back of the case.

so it appears that the main shaft in the trans is the weakest point.

A word of caution to guys running rough roads. slow down or step on the clutch if you see the tires bouncing or can see the rpm's jump when you hit the bumps.
I have never noticed this happen with both axles connected bc they cancel each other out and the shock isn't sent to the trans.

 

[54reo]

Very interesting.

Thanks for the information.

 

[gimpyrobb]

No chit! Look at that carnage.

 

[Hammer]

Crunchy!

 

[bgekky3]

Thanks for the info. I have my rear driveshaft removed. My truck sees 99% on road miles. I have not noticed any bouncing so far, but I will keep an eye out on the bumpy roads. Have you tried running the lockouts in the rear axle to see if the bouncing stops?

 

[jwaller]

Thanks for the info. I have my rear driveshaft removed. My truck sees 99% on road miles. I have not noticed any bouncing so far, but I will keep an eye out on the bumpy roads. Have you tried running the lockouts in the rear axle to see if the bouncing stops?

yes. it's much worse. the suspension design makes the front axle want to raise up when under power. it's much better to have the rear most axle doing the pulling, gives a tighter turn and less tire wear plus more MPG.

 

[jatonka]

Jwaller is absolutly correct, I have long term, high mileage experience with deuces with rear axles disconnected and agree, drive the rear rear axle, not the front rear axle.

 

[Brock Steel]

Holy smokes batman.

 

[OPCOM]

nice breakage!

 

[deuceman51]

LOL, all the more reason to not mess with a design that works. I'm really suprised at how that broke though. Thank goodness for spare parts.

 

[chipola]

pure ignorance here. would you explain how to lock or unlock rears so one or the other would pull. dud

 

[gringeltaube]

..... would you explain how to lock or unlock rears ......

https://www.steelsoldiers.com/showthread.php?12318-preventing-tire-scrub-stock-m35a2-rear-axles.html
https://www.steelsoldiers.com/showt...axle-lockout-install-twenty-minutes-tops.html

 

[Recovry4x4]

Oddly, Bjorn has been running without the inter axle shaft for many a year without a problem. Wonder if the weight of that k-boom keeps the tires firmly planted.

 

[jwaller]

Oddly, Bjorn has been running without the inter axle shaft for many a year without a problem. Wonder if the weight of that k-boom keeps the tires firmly planted.

more weight definatly helps. I was on a very rought streach of I-20 between atlanta and birmingham, AL I could look out the window and see the rear axle boucing off the ground and could hear the engine rev up between the bumps.

I wasn't careful enough to let off in the bumps or step on the clutch and it only took a few very hard powered bounces to break it.

 

[chipola]

Thank you gringeltaube, like they say a picture is worth a thousand words, and i thought i was missing a switch somewhere,dud

 

[Jake0147]

I took the advice from this site, and removed the inter-axle shaft for a bit. I would be willing to bet that on smooth roads, and low speed operation it is a perfect solution, and I would keep it removed if things were different here... But I am stuck with poor roads, lots of hills, every intersection is a hill start, and there is no way to properly control the hop from the front rear. It seems like the clutch was down more than up trying to drift over the bumps that would cause a wheel to break loose. It does OK on the bumpy roads when loaded moderately (a cord and a half or better of stump green firewood), but it will not do any more than a very modest hill start without the front rear starting to hop. (Even a "california stop" where clutch control is not an issue...). The front end can be locked in for this, but unless you're going straight through the intersecton this causes it's own windup in the rest of the driveline besides the transmission. It does MUCH MUCH better driving the rear rear instead of the front rear, as the reactive torque on the axle pushes the rear axle downwards, whereas the same torque lifts the front rear axle upwards, but it is a long way from perfect, and IMHO it is not a good plan for 75 percent of my driving.
I still want a lockout so that I can unlock it WHEN IT IS APPROPRIATE because it really does make a noticable improvement on good roads, but my accountant says no because there's other things I want more..., so in the mean time I keep my axles and driveshafts in place, driving all of the rears.

 

[JDToumanian]

Oddly, Bjorn has been running without the inter axle shaft for many a year without a problem. Wonder if the weight of that k-boom keeps the tires firmly planted.

Bjorn has also stated that he quickly flips the air toggle to lock in his front axle when he gets wheel slip back there...

We have some very bouncy slow lanes on the freeways out here... Too many big rigs pounding away at them, so I run my rear tires at 30psi. It eliminated the bounciness and I get a smooth ride.

Jon