Mr. Mindless said:
PTOs are typically a side mounted little dog gear. Not something that could be worked around.
4' sounds like real tight spacing to cram a case between. Seems to me that using passthrough diffs that are in highway service every single day, proven tech, with high horsepower high gross ratings, is really the way to go. I'd drop the rear steer idea and keep 6x6 on the table before I started cramming extra transfer cases in tight spaces.
Run it just like drawing #2 with interaxle diff lock and diff lockers in the rear axles. Extra claptrap is what you don't need in the boonies.
The t-cases I've been looking at have the PTO on the opposite side of the input so it passes straight through/couples directly in line with the input shaft. Simpler design, I guess.
Still wishful thinking that I'll end up with some ISAS axles. The centers would get hard mounted and have about 20" between the pinion flanges. 13.8" pinion flange standoff on the AT4000. Don't have the standoff measurement for the AT5000ISAS handy. Pretty much impossible with rigid axles because the intershafts wouldn't fit at all so tandem axles would be they way to go.
[486] said:
or even just 4x4, omitting the rearmost axle (set up as a drop-axle)
Got that as a possibility on #2. Drive two axles and keep the rearmost as a tag.
jd8420 said:
I thing the easiest and cheapest way to get what yo are trying to accomplish would be to just set your axles and transfer case up the same way as any front engine 6X6 is set up and try to find a v-drive like are in boats that is heavy duty enough. That ways you could use the common wide 6.83 geared Axletech 4000's. For the middle axle you could take a pass through AT4000 and cut the ends off and graft on the steering knuckles from a front axle. The V-drive could be set up with whatever overdrive ratio that you need and be used with the rear engine. The transfer cases like the AT T600 T800 and MH MVG1600 send most of the power to the rear axles. The way you have it in your diagram would send most of the power to the front axle.
I keep thinking about the grafting. Couple snags, though. The tandem axles don't show a final ratio that matches the wide or narrows. Really close, which has been done on several vehicles, but makes me go hmmm. The other is that I don't really have a place to jig the axle for welding on the inner C's. I'd have to hand this all to a machine shop to make a custom bar, weld the housing and shorten the axle shafts. $$$$ in Colorado. This has me thinking I should hold out for some TAK-4's because they're already equipped with steering and pass-through diffs. Gear ratios could be the only major downside to those.
One thing that made the T800 shine was the 50/50 split option. This caught my eye right away because I know my entire setup is facing backwards in relation to every other vehicle that these t-cases were designed for. But again, like the AT4500's, I'm thinking the T800 with my specified options is nowhere to be found in the states. Leo said he's still waiting on a response about a manual. He did send me the form to fill out so they can specify a suitable t-case for my vehicle. Doubt the price is affordable, but that might at least give me a part number.
