2-speed axles...

[jonrpick]

After seeing the recent stuff in the Garage about aftermarkets OD units, I started wondering about the 2sp axles I've heard about in big trucks.

Anything exist for a light-duty? Seems like it'd be the perfect solution to choosing between economy and power.

 

[Stomis]

What?! Any info on how they work in general you might have?

 

[77crewcab]

In general they wouldn't be available in anything less than a 2 ton axle due to the size needed for the gears. It is essentially like two sets of gears in the pumpkin (hi/low) and you switch between them with an switch controlled air actuator.

 

[original balzer]

They are not as strong as you would think either! The old 2+ ton trucks where usually under powered and sluggish, as in not enough umph to break the axle (very often anyway), but modern higher power rigs Im sure would break them.

Also I have never seen a 2 speed axle with ANY sort of traction device, and Im certain the gear ratios available are limited to just a few.

 

[jonrpick]

I guess my big question is, why do they even exist if simply regearing the tranny or using a gear splitter would accomplish the same thing?

 

[mad_burban]

ive been doing alot of reading on that ranger OD unit and that seems like it would work well as long as you dont have a crapload of torque and you dont mind cuttnig a few holes in the floor. be nice to have 8 gears instead of 4.

 

[Drey]

It would work but ive never seen a 2 speed front axle. Unless your talking one for 2wd tow rig purposes only

 

[cabledawg]

I think most of the smaller trucks are using the US Gear OD unit. My hometown had a tow company that used a pair of F350's for winter time towing and recovery because thay were 4wd. They both had 2 speed shifters attached to the stock 5spd. I gave up trying to find a 2spd rear axle for somthing as small as a pickup.

 

[Hogback Fabrication]

I guess my big question is, why do they even exist if simply regearing the tranny or using a gear splitter would accomplish the same thing?

Its just a different way of getting more gear selection, and its a dated one at that.

Using a secondary gear box with 2-4 ratios and a primary gear box with 4-8 ratios is a much lighter and cheaper way to accomplish the same thing.


Its kinda like asking why use a flathead motor when you could use an OHV motor? The OHV is way better, it was just different ways of engineering the same thing. One way was better than the other and that's what prevailed.