Rear Axle interconnect???

[emmado22]

Ok, so we all know the deuce should have it and doesnt, so why not? Can something be fabbed up out of already exisitng interconnects? I imagine there is a decent sized market for this item, as it will save alot on rear tires for those who might need the 6x6 and dont want to mess with cutting down axle shafts and the like.....

What do you think?

 

[readyman]

I'm with you, Mark.
Although I started a custom disconnect and it's on the back burner right now(working on alternator rebuild). I have heard that there is a interaxle disconnect made for the Rockwell axle setup like ours. It was used on older dumptrucks or cement trucks, might have been a Timken product. But still a junkyard item. Don't the Scandanavian M35's have them as standard equipment(has to be a US supplier)?

 

[Jake0147]

It's not so much an "axle interconnect" that you're looking for, that would be the little stubby driveshaft between the two rear axles. A power divider (a differential assembly that allows for the slight difference in rotation between the front rear and the rear rear) is not so much an added on unit betweem the twp rears, but rather a design factor in the front rear. While anything can be buit with enough time and resources, the only really practical solution would be to put the front rear from a highway truck in place of the existing double reduction rear. Matching the drive ratio is going to be exceedingly tough, which means that the rear rear will probably have to be changed as well, which is good, because your old brakes wouldn't fit so now you can have a matched set of brakes on the rear, and of course that is going to mean you need to update the front axle to similar brakes and drive ratios...

The benefits at best are going to be a mpg and (possibly) a little change, and a slight change in tire wear that is more or less signifigant depending on how "matched" your four or eight rear tires are. You'll have to keep the truck for a million miles to pay it off. So now you're looking for a more modern engine design that'll offer that performance, a transmission with a proper selection of gears to keep said engine happy with the new rears...

EDIT...
Readyman, you snuck in on me there. I had heard something of this nature when we were building 4X4 trucks on deuce axles and were trying to make our own version of the "T-rex Dodge" but without the "Dodge" part. All we could verify was that there were rumors out there. No one was able to nail down an application, forget about a source. I know that there would be loads of interest in this.

 

[Recovry4x4]

HRD has them. He used an oversized version of a driveshaft disconnect from Remco I think. It's quite simple and effective. Requires inter axle driveshaft mods only and fabbing a few brackets.

 

[jatonka]

Another simple fix is to use an axle known as a blind shaft and one lockout hub on one side of the front rear end. That effectively gives you a power divider. When you need all wheel drive, you get out and lock 2 front hubs and one rear hub and you are golden. JT

 

[acetomatoco]

attaboy JT....How much for one HUB?

 

[5tonpuller]

5 ton

I wish I could find one for a 5 ton.

 

[clinto]

RE: 5 ton

So the question is:

Is HRD's interconnect as strong as a standard driveshaft?

For me, next year (before my 10 new tires are mounted) I will be buying a set of front lockouts and a double ended axle and a single lockout for the middle rear axle.

clinto out

 

[73m819]

RE: 5 ton

i have a old MOTER truck repair manual showing timkin (rockwell) double reduction drop in axles, there is 6 axles, thay are the std and stdd ( the stdd is the duel axle setup of the std, this would have a power divider on the front third member), this looks like the 5t axle, the smaller axles are srdd, stdd, sud, and sudd, the dd units would have the power divider on the front member also, these look like the deuce axle.

it looks like we could find the right dropin for the front axle, pull the gears and install the deuce or 5t gears , we mite get away with this mod, just finding the third member would be the chore.

i have no way to scan my book so i can post pics of this

 

[Jake0147]

RE: 5 ton

My eyes are wide. From this book, can you identify if it is a power divider (inter-axle differential) or if it is a disconnect unit to simply not drive the rear rear (like temporarily removing the interaxle driveshaft)?

 

[m16ty]

R model Macks have a unit on the driveline that attaches to the rearend that works very similar to a transfer case sprag unit. When one axle spins it locks them both together. Under normal driving only one pulls. It's been a while since I've messed with one but I'm wondering if it could be modified to fit?

 

[m-35tom]

just using one lockout hub is by far the cheapest and easiest way. if you match your tires you do not even need that. spend your money on something really useful like my over drive gear set..................

 

[timntrucks]

an over drive gear set? we need more info on that as well as all the other forms of lockouts that are talked about on here. and some pics as well. with the fuel getting higher it makes us all want to be conservative. my after thoughts was if you only had the one axle pulling most of the time would that be to much of a load in it? after all it was designed to be used in tandem ? lets keep this one going so we can find some answeres many thanks Tim

 

[73m819]

the timkin is a power divider with the sliding clutch, my book shows this in a few pics and goes into overhaul detail

 

[Jake0147]

That's my thought so far, with my limited knowledge of applications and various types. Removing the inter-axle driveshaft is the cheapest, but not convenient if you ever want all the wheels to drive, and also the walking suspension would tend to unload the front axle as forward torque is appled. Better is to drive the rear rear only, which is the next cheapest option, the lockout hub option. That would allow the rear rear to be driven and the front rear to idle, which (in coming from me is according to theory and second hand reports only) would provide better tire wear and general drivability, along with being very convenient to "lock in" the idle axle when needed.
So, IMO only, a disconnectable inter-axle driveshaft would be more expensive and less effective (equivalent to removing the driveshaft), and less desirable (from an operational point of view) than the single lockout hub on the front rear.
I am intrigued by the sprague idea, depending how it works. If it could pick and choose WHICH rear to drive on an as needed basis (as opposed to always driving one and selecting the other as needed), it might be almost as effective as modern stuff. Since it would tend to always drive the "biggest" set of wheels as the tread wears off, it'd probably (disclaimer again, theory only), but probably do a pretty good job equalizing the tire wear if all the tires are not identical.

I'm working on a wait and see basis, I know I'd like to drive mine more than I will, so while an actual power divider (inter-axle differential) would be nice, I'm thinking if I end up needing a solution it'll probably be the single lockout hub. Very easy to do, fairly convenient to operate, and zero perminant modifications, and un-modifying it for authenticity purposes should I decide to would just take a few minutes and a couple of hand tools.

 

[73m819]

the mack unit is a automatic inter-axle connect, it works like a limit-slip diff.. on power divider equiped duel axles, the REAR axle drives until the power divider is locked in then both drive. in the mack unit, if you break ONE axle the truck will NOT go. in the power divider inter-axle connect, you break ONE axle (in fact you can pull both axles from a rear), you lock up your power divider and down the road you GO. all modern duel rear and duel front axle trucks us a power divider in the front rear axle and on duel front ,in the number two axle third members, mack is the only one that uses the limited slip (does not work well in dirt trucks because of the breaking axle thing. as a side note, i beleave that the 123s and 125s had the mack limited slip axle interlock

 

[readyman]

Emmado22,
But still, a couple low$ intershaft assemblies has everything you need. Can be manual engagement or a pneumatic actuator to slide the splined shafts together. Some guide tubes just have to be added to the coupling in the pics.

 

[73m819]

the support tube would have to come off the right shaft end, this would have to have a bearing for the sliding sleeve to rotate in, or it would eat itself alive, if the bearing died, this connection would fly around and take out everything between the frame rails and between the axles.

 

[readyman]

73m819,
Yeah thanks, it's going to take a LOT more engineering than I presented.

 

[m-35tom]

the interconnect idea is old, and is made for most rear wheel drive vehicles for towing. i'm sure with a little looking you could find a suitable unit. go here for some good pics of how it is made: http://www.drivetrain.com/remco.html


as to the over drive it's covered pretty good in the "other" forum on 'hot roding etc' or see http://mysite.verizon.net/milveh/transmission/overdrive.html