Just bought an '03 Impreza Outback Ts, 2.5 automatic. Had a '97 impreza previously.Owner had rigged up a swtich to go from AWD to FWD though the AWD fuse to improve fuel mileage. I put 80+K miles on it in FWD and maybe 2K in AWD. Encountered no problems. Thought I'd ask for thoughts concerning this mod prior to doing it.Local well respected transmission shop owner said no problem. Thanks for any input !

Edited November 18, 201312 yr by gazelle

Ooops ! Didn;t bother to "proof"  my own post...s/b "switchable"

It's bad for the transmission and I see no reason you'd get better fuel mileage.

Whether the center transfer clutches are engaged or not, all the rear end stuff is still turning. The hubs don't disconnect like a truck, so I don't see the point.

Outbacks changed the Duty C signal around 2003 - it shouldn't matter if you're just installing a switch for the FWD fuse holder, and often times Imprezas receive changes later than legacy's...but proceed carefully depending how/what you're doing.

 

There's no point in doing it.  All the rotational elements and weight are still in place so it doesn't improve gas mileage.

I've done it before...though usually for more practical reasons - like a failing driveshaft ujoint.

 

Probably costs more money in slightly worse tire wear due to having only one driven wheel.

 

It does cause the Duty C to be powered constantly, putting more "miles" on it, but it probably would be fine.

 

The better switch to install is a Duty C switch which "locks" the 4WD when you want it....but then there's the 2003 signal change issue to check first.

The solenoid switchover can eb checked by putting in the FWD fuse then checking the voltage on the solenoid circuit/pin at the TCU or elswhere.

 

FWD fuse with +12V to the solenoid = 'old style',    0V to lock-up, +12V to disengage

FWD fuse with     0V to the solenoid = 'new style', 12V to lock-up,     0V to disengage

The solenoid switchover can eb checked by putting in the FWD fuse then checking the voltage on the solenoid circuit/pin at the TCU or elswhere.

 

FWD fuse with +12V to the solenoid = 'old style',    0V to lock-up, +12V to disengage

FWD fuse with     0V to the solenoid = 'new style', 12V to lock-up,     0V to disengage

excellent, thanks Dave!

Thanks to everyone for the reponses. I''ll probably leave well enough alone.