[bennelson]

In all my thoughts about ways to improve my plain-jane Chevy S10, the one thing I am still not sure about is the efficiency of 4-wheel drive.

I POSSIBLY MIGHT trade my 2-wheel drive S10 for a 4-wheel drive version to do my bio-diesel conversion.

What I am mostly wondering about is how and why 4-wheel drive gets such worse economy than simple rear-wheel drive.

Pardon my ignorance here, I have never owned a 4x4. My understanding is that a traditional four-wheel drive has an engine in front which goes to a transmission, then to a transfer case. From there power normally goes straight through to the driveshaft and rear wheels. If the four-wheel drive mode is selected, the power gets split at the transfer case between the rear and the front wheels. I still am not sure of how "push-button" vs locking wheel caps/covers?!? works.

So, is 4-wheel drive less efficient because:

1) it weighs more - transfer case, front half-shafts etc.
2) power is always going through the transfer case - more moving parts, friction, etc.
3) wind resistance - 4x4s always look really jacked up
4) All of the above?
5) Other - something else I'm missing?

Now part of why I am wondering this is that it seems like a 4x4 would be easy to make into a hybrid - gas or diesel runs one set of wheels, and electric runs the other.

For example, could the rear drive shaft be be removed, hook a (powerful/high voltage) motor to the rear differential and let the gas engine run the front wheels?

Does this cause transfer case wear and abuse?
Would you actually make a front wheel drive pickup just by disconnecting the rear drive-shaft?

I have also heard that diesel is rather efficient under load. Does that mean that a 4-wheel drive diesel pickup would take less of an economy hit than a gas 4x4?

Just curious about all this stuff.

Thanks,

-Ben