If one were to run two driveshafts from a common t-case, obviously the rea differential would have to be offset, but how would the driveshaft clear the front axle?
Not front steer axle, but the front, rear axle. LOL.
Dave, why do you have to come up with some crazy concept like this? LOL.....

 

After this thread started I searched around trying to find out what others had done. Surprisingly, many of the the trucks ran some sort of steerable 2nd axle. Somthing about helping the turn radius. I cleared my browser history since last night or I wouldve posted the links.

I agree a dual driveshaft xcase would be easiest and would have to have left offset front pumpkin and right offset rear but wouldnt the rear axle drive shaft hit the front axle tube unless the truck was lifted quite a bit?

 

Heres the transfer case idea.

You know me Ed nothin is ever easy. I just thought of this last night and i was like well ill just see if anyone has done it. Obviously its got us digging in our brains to see if we can figure it out. Well back outside i must go. Im pullin the rear out of the ol CC.

 

How about that! pretty engenius! Now is that an actual transfer case or is it just a splitter for the rear drive shaft?

 

Dont know really. I got that from the link on the first page of this thread. The thing is if you use a transfer case then you would have to turn it around so wouldnt that make it spin backwards?

 

that thing in post #18 is an adapter with a through shaft on top, and chain driven lower gear to the front diff.

 

Start with two transfer cases bolt the rear output of the stock one to the output on the second one then you have two outputs facing the rear, Put two offset differential rear ends(or one front driveshaft lockout the steering!) with high pinions flip one upside down. So you'll have a left high driveshaft and a right low driveshaft! Are you following me? Don't go with a hendrickson suspension they suck! Take your leaf springs and flip them so the axle pad goes to the frame and the shackle ends connect to the axles (like Mack rears) You try it and get back to me I will take 20% of the profits if you can sell them!!!

 

Stupid I posted before I saw there was another page!!!!! DOhHHH!

 

TJC, it is an adaptor, but it is gear driven, not chain. It is a 1-to-1 ratio direct drive box. A chain drive setup would not be reliable for long term and/or high speed usage.


Blue Beast, you mean something like this?


How about this, using air bags.

 

[QUOTE=miker67]TJC, . A chain drive setup would not be reliable.

203's are still in use and are hard to beat. They take a ton of abuse, and are chain driven. Depending on the case you have under your truck now, I would be willing to bet that it is chain driven.
Chains are strong, and fairly reliable.

 

75f350, you are correct they are still in use and are reliable, for their designed purpose. Since the primary drive portion of a chain drive t-case is straight through, in one side and out the other, it takes little wear and tear. However, the chain portion that drops to connect to the front axle output only operates part of the time, so it can take a lot of strain and use, but it is not designed for highway speeds, and not designed to last for hundreds of thousands of miles. If it chain were used in an application for a full-time four wheel drive, it would stretch and get sloppy, and then other issues would come up. This is why every full time setup I have seen relies on a gear driven setup. You are correct, I have several vehicles that are 4x4's and I think they all have chain setups, and I would agree that they are stong and reliable when used as they were originally intended to be used, which would be to provide power to a front drive axle for short durations only.
I did not post what I said to stir things up, merely to point out that in the specific application being discussed, I do not believe that a chain drive is adequate for longevity purposes. This being the rear axle and the primary drive axle, any gear box used will be spinning on both ends for as long as the vehicle is in use. I think that if one could find a gear driven box, with a little machining it could be adapted for these purposes. The only trouble is all the good gear driven boxes are REALLY heavy and there would be a lot of rotational twist problems to deal with since the box is designed to be mounted from the top, not the bottom output.

 

[QUOTE=miker67] Since the primary drive portion of a chain drive t-case is straight through, in one side and out the other, it takes little wear and tear. However, the chain portion that drops to connect to the front axle output only operates part of the time, so it can take a lot of strain and use, but it is not designed for highway speeds, and not designed to last for hundreds of thousands of miles. If it chain were used in an application for a full-time four wheel drive, it would stretch and get sloppy, and then other issues would come up. This is why every full time setup I have seen relies on a gear driven setup. I do not believe that a chain drive is adequate for longevity purposes.

Unless the 203 has been converted to a part time unit, it is always in 4wd, and the chain is always in use. It never stops.
I am not rying to argue either, and merely posting an opinion. I do believe the gear set up would be desireable, but do not believe the chain is so far out of the question.
I do also agree that rotational forces would be pretty extreme.
However I do like the idea (for purposes of this thread) of the "in-n-out" box mounted to the first pinion. It solves the driveshaft clearance issues, but that box has to be as much money as a pair of rockwells. LOL

 

I agree, rockwells are the ticket for this application. It eliminates all of the concerns associated with this mod. I have a 67 dodge power wagon that I am probably gonna do this conversion on. It has a stepside bed and since it was made in the 60's all those fenders are just bolt on. That makes it a perfect candidate because it is nothing to bend some new fenders on a sheet metal brake and bolt them in. I just wish rear steer was road legal.

 

> In the big trucks they call this differential lock. When you engage both rearends.

FWIW

On the tandems it is more like AWD, when you flip the switch it becomes more like 4x4. The axles themselves are not locked. Unless it is like a septic truck (they can come in true 6x6 with three locked axles ) about the only ones with locked axles on demand are single axle tractors.

 

4 Wheel steering is road legal! Nissan 300zx have 4 wheel steer. You have to lock it out for high speeds or else when you changed lanes it would rip you over into the next three lanes unless you make it turn the opposite way so it crab walked(same direction as fronts for high speed, opposite direction for low speed tight turns) Miker thats what I was saying like a Mack dump truck. The Mack axles can move(1") on the spring to take lateral stress off the springs while turning and supposedly it helps turning radius!