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Oshkosh MK23, 25, 27, and 28 with TAK-4:

3.556:1 planetary wheel hubs which are the exact same ratio as the common AxleTech 4000's. Swappable, I'd say. There's a few noticeable between the internals of the end plates.

1.687:1 R&P ratio. TAK-4 and AT4K diffs look identical. Possibly swappable, too.

5.999:1 overall ratio. I would find a way to lock the wheel hub gears, which would give me a 2.14:1 axle ratio. Stock is 3.33:1

30000 series transfer case. 1.27:1 underdrive, single speed. 32/68 planetary torque split. If I acquired one, I'd open it up to see if the diff can be flipped around. With a rear-engine bus, everything is backwards in comparison to the vehicles that use the drivetrains that I'm considering.

Put those ratios together with our Allison HT740D and loaded Michelins that revolve 491 times per mile and you drop the engine rpm to about 1,300 at 70mph. About 100rpm below peak torque rpm, which I'd call a decent win considering what I'd be working with. Them military trucks are geared low.
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.
 

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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.
well, flip the whole housing and rework the mounts
 

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I would find a way to lock the wheel hub gears, which would give me a 2.14:1 axle ratio
...
Put those ratios together with our Allison HT740D and loaded Michelins that revolve 491 times per mile and you drop the engine rpm to about 1,300 at 70mph. About 100rpm below peak torque rpm, which I'd call a decent win considering what I'd be working with. Them military trucks are geared low.
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
 

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Discussion Starter #1,544
Got some corrections to make.


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.

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.

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.
 

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Too bad you dont have more room between the axles. T600 between the rear axles, drive on rear axle with the front output and drive the other with the rear output. Drive the front axle with the PTO output (in high range only).
 

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Discussion Starter #1,546 (Edited)
Too bad you dont have more room between the axles. T600 between the rear axles, drive on rear axle with the front output and drive the other with the front output. Drive the front axle with the PTO output (in high range only).
That's pretty similar to what I had laid out in the original plan when I was intending to use AT4500's and later wasn't aware that tandem axles had 50/50 diffs in them. Might go back to that. Looking a AT4500's again since they're close to half the weight of a TAK-4 and have some sweet disc brakes. No drive-through diffs, so a t-case with center diff would need to go between axles. Probably a lot easier to match up gear ratios that way and I might even stack t-cases to achieve the correct high range ratio and brag out having doublers on a bus when I crawl to top of gnarly camping spot and campers up there go nuts when the see us coming.
 

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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.
New to the thread (thank you for your transport thread to get me in here), but I'm glad to hear you're sticking to the crazy vision vs being practical - I learn more from "crazy" than cookie-cutter stuff.
 

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New to the thread (thank you for your transport thread to get me in here), but I'm glad to hear you're sticking to the crazy vision vs being practical - I learn more from "crazy" than cookie-cutter stuff.
This is great. You're in good company, sir. I was going to delete the transport thread last night, but got very occupied. Perhaps it is best that I leave the thread and report back when I find my final solution.
 

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Been a while, hasn't it? I was in OKC for a week. Came back to minor blizzards. Freezing fog for the last few days. Getting outbid on trucks. Finally got to look over a couple F350 Superduty trucks in Denver last night and brought this one home. 6.0, ZF6, 4x4, said to have the F450 axle swap, already set up for Hot Shot work which I've been considering for a while. About half an hour on the phone with USAA to get insurance on it this morning because the VIN was changed a bit at some point for the upgraded GVWR. And now all El Paso County DMV's shut down as of this morning because, well, I'm sure you all know. Can't seem to get plates or temps for my truck until some time next month and I need them like yesterday. Either way, it's nice to have something that can haul.
 

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It’s CO. When I bought a car there 7ish years ago I didn’t need plates for 48hr by law.

I did get pulled over and trooper wasn’t familiar with that. He let me go though.
 

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It’s CO. When I bought a car there 7ish years ago I didn’t need plates for 48hr by law.

I did get pulled over and trooper wasn’t familiar with that. He let me go though.
I have to drive it across several states to pick stuff up if we bid on it, hence I need registration right now. Bought it for exactly that purpose and damn if we didn't hit yet another wall. Can't put it in my name, get temp tags or any such thing until the DMV opens back up. Colorado only lets you register from the county that you reside in. Thinkin'.
 

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I have to drive it across several states to pick stuff up if we bid on it, hence I need registration right now. Bought it for exactly that purpose and damn if we didn't hit yet another wall. Can't put it in my name, get temp tags or any such thing until the DMV opens back up. Colorado only lets you register from the county that you reside in. Thinkin'.
I have heard S. Dakota is nice...
https://yourbestaddress.com/sd-vehicle-registration.html
 

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Don’t go through an agent in SD. Unnecessary.call Pennington County clerk. They don’t have a wheel tax unlike some other SD counties.

It’s not the cheapest but it sure is easy. I’ve never been there. But... yeah.
 

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Pennco.org
I'll give them a call in the morning. Just so we're on the same page, I can call them up, tell them I live in Colorado, just bought a truck with a Colorado title and they can provide the steps to register it through them? I've seen plenty of full-timers register their domicile and converted bus with SD because they're completely open to it. As far as daily passenger vehicles/LD trucks, I don't know.
 

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sounds like a good reason for you to not have a registration for a truck on your trip.

fuckem.
Pretty much. I've got plenty of documentation on hand proving that we bought it in agreement. And of course you can call up the DMV and listen to the corona virus message.
 

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Pretty much. I've got plenty of documentation on hand proving that we bought it in agreement. And of course you can call up the DMV and listen to the corona virus message.
I'd say run it. We have a car with temp tags now, if they don't reopen before the temp tags are up we'll just keep driving it. It would be pretty easy to fight that ticket because there's no where legally open to pay the state their money.
 
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