'97 CR-V: Removing rear driveshafts?

I been approached privately by someone who was told that he could improve
his gas mileage by removing the rear driveshafts in his AWD CR-V.

Beyond telling him some basics, I could not answer his questions about
potential damage to the drivetrain. So with his permission I'm posting the
question on his behalf here.

What he asked me:
"I have a 1997 Honda CRV (automatic trans). Someone told me that if I
wanted to improve the fuel economy, I could remove the rear driveshaft (as
I really don't need the AWD feature). Supposedly that way the engine
wouldn't be turning extra parts. Would this work? Would the transaxle
send all the power to the front wheels? If so, would it be in a slip
condition all the time and burn out? Or would the car just sit still as
the transmission spins the rear yoke that's attached to nothing? Thanks
for any help you can give me."

 

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He's have to remove both drive shafts and the propeller shafts. The
differential could even be removed, to save weight. He might need some
busted-off outer rear CV joints to hold the rear bearing assemblies
together and to prevent the ABS from going into cardiac arrest..

When he sold it, he could say 120,000 on the car, only 50,000 on the
rear half of the drive train.

'Curly'

 

so what are we looking at here for a percentage gain in fuel economy?

 

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Fuel mileage gain, maybe 6%.

Same as leaving mother-in-law at home (but she won't get out and push
HALF as good as the AWD will)

'Curly'

 

Curly, see your email.

What about the yoke on the transmission? If you removed the propeller
shaft, what would keep the yoke's splines from trying to fall out of the
gearbox?

 

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I checked the manual . . The transfer case is like a little
self-contained manual transmission . . When you unbolt the propeller
shaft from it, it just sits there and spins it's output at the same
speed as the front wheel output.. It's not like a CV joint, which is
held in place with a snap ring. I've heard of guys using an AWD tranny
to replace a FWD tranny . . They just have a funny extra spinning flange
on the backside of their (front) differential.

For the tiny bit of fuel mileage regained, it's a whole lot of trouble
to do the conversion in question, unless the person never encounters
snow, mud, or sand anyway.

'Curly'