My Suzuki WagonR Model 2013 is 4WD. My mechanic says to remove 4WD shaft. Because it will improve my car,s fuel economy and acceleration. Is it safe and plausible ?????,
Older Subaru models could be put into 2WD by removing (or adding; I forget) a jumper fuse in the fuse box.
I doubt that is still true in 2013. In any case, I would not suggest you disable AWD in a Subaru by removing a mechanical shaft.
I honestly do not think your fuel economy and acceleration will be much improved. Most of the torque is directed to the front wheels, so crippling the back half will not amount for much. The mechanical stresses to the remaining transmission/drivetrain components "freewheeling" are not easily predicted.
Subaru has one of the best AWD systems available, and the vehicle was designed to operate in this manner.