(FWD) FRONT WHEEL DRIVE {OPTION} ?

[myinhousebigdog321]

HI, ON MY '97 LEGACY L, UNDER THE HOOD, PASSANGER SIDE, NEAR BACK OF ENGINE IS A SMALL 1/2" x 1"

BLACK BOX, PRINTED IN WHITE LETTERS, ......FWD. I WAS RECENTLY TOLD BY MY MACHANIC THAT IF I PUT A 20 AMP YELLOW FUSE IN IT, I CAN NOW RUN MY CAR IN FWD, NOT (ALL-TIME) AWD, UNTIL WINTER COMES BACK! THAT I MAY GET BETTTER FUEL ECONOMY? SO, I JUST DID THIS BUT NO TELLING IF I SEE A DIFFERENCE YET IN MPG.

BUT MY (MAIN) QUESTION IS.......ON MY '03 LEGACY L, 2.5, DOES THIS CAR HAVE THIS SAME BOX? I DON'T SEE IT WHERE MY '97 WAS! JUST WONDERING IF THIS (YEAR) NO LONGER OFFERS THIS OPTION/BOX?? IF SO,...PLEASE, CAN YOU EXPLAIN WHERE IT IS LOCATED, IF AT ALL?

THANKS!

 

[A_racing_driver]

I'm no expert but that sounds like shenanigans to me

[1 Lucky Texan]

It's for when you must use a different sized spare tire, or mix in a tire of a different size or possibly for some special diagnostics.

 

you won't save any gas or otherwise benefit from using FWD under normal circumstances. You're still carryin g the weight and turning all the parts of the AWD system when in FWD mode.

[Fairtax4me]

If your 03 is an automatic, it does have that capability as well, they moved the fuse holder to the main fuse box.

As said before, no, it will not save you any gas.

[idosubaru]

+1

no gas savings. 

 

a mechanic said this?  wow

as a humorous illustration - put the FWD fuse and (maybe ask your mechanic these questions so he can understand):

 

1. are the wheels still rotating when the car is moving?

2. are the rear axles, which a FWD does not have, still moving in an AWD vehicle?  (yes)

3.  is the rear differential (which a FWD does not have) still being driven?  (yes)

4.  is the driveshaft (which a FWD...yep, you guessed it, does not have) still turning? (yes)

5.  are the internal 4WD transmission clutch packs and driven gears (which...yes sir, a FWD does not have) still in place? (yes)

6.  do the 4WD components magically disappear when the fuse is installed: the 4WD rear extension housing, driveshaft, axles, rear differential, beefier rear bearings/knuckles?

no - they do not magically disappear so the car is hundreds of pounds heavier than a FWD counterpart.

 

all of those components add weight to the system and are rotational components still mechanically fixed to the rear wheels. 

 

there are no gas savings to be had, probably best to leave the car in nominal operating condition without the FWD fuse unless it's necessary or actually performing something useful.

Edited May 4, 2015 by grossgary

[Suzam]

This topic comes up every so often, it goes back to the older 4 wheel drive trucks with locking hubs.

 

These 4WD (note not AWD) vehicles need a transfer case shifted to 4WD to engage the front drive shaft, resulting in drive power going to the front differential which drive the wheels which was the reason for the locking hubs.

 

If the hubs are not locked the front wheels spin freely because they are disconnected from the front differential which means that when the transfer case is disengaged from the front drive shaft the whole front drive system is dormant the only thing is the weight of the system itself is reducing MPG. This results in no drag loss while the vehicle is rolling. If the front wheels were locked but the transfer case not engaged the differential and front drive shaft would spin and be creating drag resulting in less MPG.

 

This is not the way Subaru AWD works since it is engaged at all times but in the case of the automatics it is controlled by electronics as to how much drive goes between the front and back wheels.

[nipper]

If you want better MPG, get a 2wd car. Otherwise you pay the penalty for AWD (and the best mileage for an AWD car) 

[Subasaurus]

If you want better MPG, get a 2wd car. Otherwise you pay the penalty for AWD (and the best mileage for an AWD car) 

agree