Got some corrections to make.
02rexwi said:
I wouldn't count on the wheel end gearing swapping. It's very similar, but not quite enough to swap.
Again, I don't think the R&P would swap, but it is VERY close to Axletech
5000's. The 4000 housing is different...
Flipping the differential in the t-case would only flip the torque proportion to the other direction (more torque to the front axle). Rotation direction would stay the same. You could flip the differential housing in the side-to-side differential. This would be easy on a non drive-thru carrier. The drive-thru carrier would require a different housing.
As for locking out the wheel end gearing. It could be done in theory, but your ratio isn't correct. You'd be left with only the ring and pinion ratio of 1.68:1. This would also put a lot more strain on everything upstream of the wheel end planetary. None of that was intended to be transmitting that much torque.
Forgot that AT4K hubs are four-pinion and the Oshkosh are three.
Being a pusher bus, the t-case input would face the rear, facing the 68% towards the front axle. I'd much rather find a t-case with a 50/50 diff. Still working on it. Being able to spin the proportional diff around would suffice.
I know that the wheel hubs reduce the driveline torque a ton. Theoretically locking the hubs to get a better ratio was the best I had come up with so far. Double t-case to achieve double overdrive might work out much better. I haven't come up with any other combo to work without swapping the trans to what the MTVR's use. The ratio is actually correct. I made a confusing typo. 2.14:1 comes from the 1.27:1 t-case and 1.68:1 r&p. Still too high.
[486] said:
well, flip the whole housing and rework the mounts
If we're thinking of the same thing, indeed. I'll chop up anything the make what I'm after.
[486] said:
I don't see why you're going to all the effort of AWD when it isn't going to be able to pull itself over much of anything with those kind of ratios
It's just that you're adding all this driveline loss, and knobby tires that ensure that it'll get 4 mpg or worse, then you're seeking out axle ratios that make the top gear of your very limited ratio spread borderline useless (you are running an allison, right?) in the search for fuel economy.
Not trying to be a debbie downer, but I'd be real tempted to give it a go with a lift axle in the rear and a locking single diff with some real mean concrete/garbage truck drive tires
Agree that the overall ratio of that combo is disappointing. 4th gear would bring the suck. I'm not running knobby tires (referring to XZL's?). I'll be running OTR 42"ish tires which are 10" shorter than XZL's. Haven't once been after increasing fuel mileage. 5mpg is pretty much tops for the buses with the 8v92 and I expect to see less. I'm still going straight for drive axles all the way around. Just gotta get that gearing pinned down. It'll happen.