Driving with AWD off and on

[coloradosubarules]

As yall may know I have a 90 Legacy L Wagon AWD Auto. Seeing as to how I was a professional car audio installer and am now an MCSE IT Consultant, I installed a toggle switch and in-line fuse for my AWD override under the hood. I nver really thought about the effects of doing this though. Is it safe to engage and disengage while at low and high speed? Should the vehicle be in park only? Does it matter if I do it with the car running? Come on Scooby junkies....step up to the plate on this one. No guesses please. I need solid facts. I am most likely going to be selling her soon, or making it a semi-rally car but I would still like to know.

 

I don't think my wife would let me keep three cars for off-road only.

[LosDiosDeVerde86]

As yall may know I have a 90 Legacy L Wagon AWD Auto. Seeing as to how I was a professional car audio installer and am now an MCSE IT Consultant, I installed a toggle switch and in-line fuse for my AWD override under the hood. I nver really thought about the effects of doing this though. Is it safe to engage and disengage while at low and high speed? Should the vehicle be in park only? Does it matter if I do it with the car running? Come on Scooby junkies....step up to the plate on this one. No guesses please. I need solid facts. I am most likely going to be selling her soon, or making it a semi-rally car but I would still like to know.

 

I don't think my wife would let me keep three cars for off-road only.

i would say that there's a reason why my parent's GMC Yukon won't go into 4x4 if it's in motion. i would imagine that what you've hooked up is pretty much the same thing (a push button that goes from 2x4 to 4x4) if i were you (sorry for the "guessing") i'd play it safe and do as the SUVs do. have the car running, in neutral, and not moving.

 

and that is a very educated guess.

[coloradosubarules]

I installed it apon moving to FL so I could turn it on and off when it starts raining (FL drivers foreget how to drive when the roads turn wet) so I am more prepared than grandpa in his caddy. I haven't used it yet but I am tempted. Anymore thoughts?

[LosDiosDeVerde86]

but my question is...

 

would installing the fuse improve gas mileage?

 

i was talking to the guys at work about this and one said no and one said yes.

 

i would thinkg that it would because the engine is powering less parts...the whole rear end...one of the guys agreed.

 

now, the other guy said that running it with the FWD fuse in would cause the same, if not worse gas mileage because it's not like unlocking the hubs on a pickup, the engine still has to pull all the parts in the back, thus needing more power.

 

what do you guys think??

 

 

(sorry...i might be taking over your thread....)

[LosDiosDeVerde86]

I installed it apon moving to FL so I could turn it on and off when it starts raining (FL drivers foreget how to drive when the roads turn wet) so I am more prepared than grandpa in his caddy. I haven't used it yet but I am tempted. Anymore thoughts?

why not just leave it on?

 

that, after all, IS the beauty of Subaru All-Wheel-Drive

[coloradosubarules]

For the most part I run with it off. The power split is 90 front and 10 Rear. I noticed it saves more on my tires the most but it does help the gas situation.

 

 

Hope this helps.

[THAWA]

duty solenoid c, start saving to replace it, search and you'll find out what i mean.

[Setright]

Why would you want to run without the AWD? You might need it around the next corner. That's like switching off the ABS because you don't feel the need during normal driving.

 

If you want to save on fuel bills, don't buy a boxer-engined four-wheel-drive vehicle.

[Legacy777]

do a search....others have tried this....it doesn't save much on fuel.

 

Also, as thawa mentioned, you're sending 12v constant to the duty c solenoid. It's meant to see a pulsed signal. It's going to wear out much quicker in that scenario.

[PAezb]

I have contacted several dealer service departments in my area to ask those 2 questions

 

1) Does leaving the FWD fuse in all the time help the gas mileage?

 

And

 

2) Can you damage any part of the drivetrain by doing so?

 

 

All the techs answered that they did not know whether gas mileage would improve.

 

All but 1 of the techs stated they do not recommend leaving the cars in FWD for extended periods of time as damage may result. The other tech simply did not know - an honest answer.

 

Interetingly, while the duty solenoid does take on added stress by leaving the car in FWD, I was told it's the clutch packs (2 of them - 1 for the front and 1 for the rear?) that would be prone to problems. The prime example given would be going back to AWD after running in FWD for a long time can lead to the classic torque bind problem. The Subaru AWD systems are particularly touchy, and everything in the driveline needs to be in sync in order to be working properly. Uneven wear in the clutch packs/transaxle/tire circumferences etc can/will affect the operation.

 

So, the bottom line is from what I've been told by the people who should know (in the professional sense) is leave your Subaru in AWD.

 

Paul

[blitz]

About a two years ago I did some searching on this subject and came across someone that manufactured a simple kit which allowed all three possible modes (manual FWD, manual AWD, & auto AWD) to be driver controlled with a toggle.

 

I kinda liked the idea of being able to manually engage the rears in advance to maintain better vehicle control on the really slippery stuff. The auto engagement of the rears is often too late and too sudden, causing initial understeer followed by a very unexpected transition to oversteer.

 

I never bought the kit, and I can't recall any info on the name of the company, nor do I know if it's still available. You might wanna seek it out to get more insight into whether or not the solenoid is capable of continuous "on" operation or not. It would be stritcly a matter of whether or not the solenoid coil will overheat.