When I worked for the Missouri State Highway Department, I drove 2.5T flat bed dump trucks. These trucks had a switch for changing the rear axle gearing. I never got a look inside one of these axles and I was wondering if this is a viable option for us Off-roaders. I would imagine that you could have a hi and low rear axle gearing with the front to match the low gearing. Hi for the highway 2wd and low for 4wd. Anyone else ever thought of this?

Those are pretty large axles with questionable off-road streanth and modification options. cool "idea" though. at my work we have a cube truck with one of these axles.

I wasn't thinking of using the axles, just adapting the double gearing to a 44 or 60 (if possible). I'm hoping someone has cracked one of these open and could describe how it works.

Originally posted by Archie_G
I wasn't thinking of using the axles, just adapting the double gearing to a 44 or 60 (if possible). I'm hoping someone has cracked one of these open and could describe how it works.

Not a chance. you'd have to engineer something like that from the ground up for it to be anywhere close to reliable.

and why have it as unsprung wieght

Unsprung weight?!?!?! Come on! I am talking about doing this on a D60! How does it work? Does anyone know? Does it have two rings that the pinion switches between or what?

Never having pulled one apart, I don't know exactly what's in one of those axles, but I'm guessing it's some sort of planetary gearset inside of the ring gear. You could set that up to be selectable and it would give you the required gear reduction. If that is the case, you might be able to shoehorn the carrier into something else if its small enough.

As far as the unsprung weight, I wouldn't worry too much. That's more weight low to lower the CG and stick you to the rocks!

-John

Some of the old Ford truck (1970's) manuals at the library have exploded views of these axles. You could probably figure out how it worked be doing a little non-internet research there. There are Eaton or Rockwell rear ends (i forgot)... I saw these pictures when I was finding an exploded view of a Dana 60 from a 78 f-250 in a ford truck manual to figure out where an oil slinger went in the diff.

Originally posted by Archie_G
I wasn't thinking of using the axles, just adapting the double gearing to a 44 or 60 (if possible). I'm hoping someone has cracked one of these open and could describe how it works.

Oh well in that case I'd say it's at least worth looking into. I bet those internals would be really cheap out of a junkyard (I know where there's a couple of these) Anyway if you find anything exciting keep us posted.

Hmm, what about using a Plantery gearset on the Pinion? with a little thought you could make it like a Auto tranny

I've got a gearvendors OD on my tow rig. Works just like a two speed rear. It bolts onto the back of the transfer case, so you can only use it in 2WD. It's long, but not really a problem on a long bed truck.

think if you could retube them. and shave them a ton! and get two with the same gear ratios. you could do it!

i think that they work because they have to different ring gears that they can change when they pull a cable. to switch.

the pumpkins are huge, you have i to have the clutch in and you probably know how to drive one anyway!:smokin:

no they dont have two ring gears, just one. it works a little like a planitery gear, ethier to gear up or down. not both. one gear is always direct in a two speed. their is a collar that moves side to side that locks or unlocks the gear up or the rear down mech. yes they are pretty big, but snipers or scorpians (not sure wich one) use 21/2 ton axles and they are much bigger

a buddy has a two spped rear axel in his IH load star and the axel is HUGE :EEK: