Question about AWD

I've been lurking in this ng for a few weeks and now that I've bought my Subaru, I begin to remember comments that I wonder if I need to understand better.

For example, some time back, one of the knowledgeable posters mentioned a "situation" in which a Subie owner might want to cripple AWD and use FWD only. I believe the suggestion was to pull a fuse, or press a switch, or ???

But I forget what! Old too soon, schmardt too late!

Could the original source, perhaps, refresh me on that?

In What situtation would I want to use FWD only and HOW would I cause that to happen on my Subie?

Any help?

Reply to
GTT
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wrote:>

While I am certainly not one of those "knowledgible" people you are referring to, my owners manual says that if you have AT, stick a spare fuse into the socket to dis-engage the drive to the rear wheels, so that the car can be towed by lifting only the front.

There is no way to do this with MT.

-- Dominic Richens | snipped-for-privacy@alumni.uottawa.ca "If you're not *outraged*, you're not paying attention!"

Reply to
Dominic Richens

Never heard of the ability to do it. But why would you want to? It won't aid you in any way apart from causing you to not have the best traction setup that the car can give you.

Reply to
martin foster

This is necessary becuase the spare tire is smaller. If the spare is put on the rear, you need to disengage the RWD. I believe I saw this in the latest issue of Drive, or it may have been in the manual.

Reply to
Alan

This does NOT make the car safe for towing. I repeat it does NOT make it safe for towing.

It allows the use of the temp spare tire on the rear of an automatic equipped car. Due to the difference in transmissions, it's not required for a manual

Reply to
Cam Penner

Not sure who the original poster is, but Subaru recommends using the FWD mode when using the (small) spare tire. It's in my owner's manual. You do it by putting one of the spare fuses in the FWD slot in the fuse box. No fuse = AWD, fuse = FWD.

Hope this helps.

Nicolas

Reply to
Nicolas Dore

Cam is right. Additionally, you need to do this if the 'donut spare' OR ANY DIFFERENT SIZED TIRE is used FRONT OR BACK. THis applies to AT vehicles only. There is a spot in the underhood fuse box (older models maybe somewhere else? anyone?) which needs a 15 (maybe newer models 20?) anp fuse put in it to enable the duty 'c' solenoid permanently. Thsi keeps the car in FWD mode so the center diff 'clutch pack' in the tail of the AT doesn't burn up from thinking a wheel is slipping all the time. This relates to why these cars should be 'flat bedded' when 'towed' AND why the tires should have proper pressure and be the same style and circumference(within very close tolerances some say 1/4"!). Do a search at

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forums for more info.

Carl

1 Lucky Texan

Alan wrote:

Reply to
Carl 1 Lucky Texan

Yessir, that was the suggestion I referred to. And you must be more knowledgeable than I am! Thanks. Do you happen to know what a "spare fuse" refers to? I'd suspect a spare fuse would be "good" rather than blown, and sticking a good fuse into "the socket" would accomplish what? (if I knew which socket "the socket" was, even.)

So you see, you are still a few miles ahead of me on this. Thanks for the note.

Reply to
GTT

Well, one reason was mentioned by a previous post; being able to tow the car with the rear wheels disconnected.

Another might be driving on ice or snow when one has put chains only on the front wheels.

May be others, I can't think of any right now.

Reply to
GTT

I suspect you are correct. My manual is very specific, tow the car on a flatbed only!

But Foresters come with a full size spare, so that may be why that is not included in my owner's manual... no need to compensate for the little donut spare!

Reply to
GTT

Thanks, Carl.

I guess I should have started with the fact that I've got a Forester and the spares on those are full-sized. Probably the reason this is NOT in my manual (at least after my extensive reading of that book)... I see that another post has identified the fuse slot by name. Now I may be able to find it.

I wonder, what the difference in front to rear size makes when placing chains on the front wheels only? Seems like that would make more than the specified 1/4" inch difference in circumference? Why does that not concern the drive system? Hmmm. That was my initial concern, anyway.

Reply to
GTT

The original poster was me. And I appreciate your comment. It puts me right into the matter.

Thanks!

Reply to
GTT

I admit to being ignorant of the fact Foresters had a full size spare - kinda cool actually. But I definitely wanted you and other readers to know you really should not tow a Scoob AWD AT with ANY wheels on the ground(especially just 2). The owners manual for my OBW claims that you can place the vehicle in neutral and tow about 31 miles at a speed of less than 20mph. That hardly seems useful so just wait for the flatbed. Try to have your spare included in the tire rotations. I suppose that since the manual says to keep your speed under 19mph with the chains (coupled with the fact you would presumably be on ice or other poor traction surface) the engineers figure there would be less chance for 'torque bind' to build up or otherwise place damaging amounts of stress on the center diff. Just a guess on my part. With such reduced traction in the rear compared to chains in the front, the TCM will just shift most of the torque to the front anyway I'd guess. If I had to do a lot of tire chain driving I'd probably put the fuse in anyway. See if there is a discussion in your manual listed under 'temporary spare'. That's where it is in my manual. As you say, it just may not apply to you.

Carl

1 Lucky Texan

GTT wrote:

Reply to
Carl 1 Lucky Texan

Just in case anyone is reading, or searching this thread on Google later.

Putting the fuse in to "disable" AWD does NOT - and I repeat *NOT* make the car safe for towing with two wheels on the ground.

NEVER EVER EVER do this.

(clear enough?)

Reply to
Cam Penner

Oops! Sorry, I think it was me that recently posted that.

-- Dominic Richens | snipped-for-privacy@alumni.uottawa.ca "If you're not *outraged*, you're not paying attention!"

Reply to
Dominic Richens

i read this in the manual for my legacy too. but i have a manual transmission. what do i do if i have to use the stupid little spare? i asked the dealer and they said just to use the spare. but if i can't open up the center differential somehow i'm afraid i might burn something up running a little spare on the highway. does anyone know how manual transmission drivers are supposed to handle the small spare? or should we just wait for the flatbed to come?

thanks! mike

Reply to
Mike Deskevich

Mike, wouldn't you think if they just wanted you to wait for the flatbed, they'd never have put the donut spare in the car? The manual must say something about it. Ask your service folks where you bought it.

Reply to
GTT

In my "tour of your new car", we were given the fuse talk, and then told that it only applied to automatics. Manuals, due to the different type of differential, didn't need the same treatment.

Reply to
Cam Penner

Reply to
Paul Pedersen

I was told, though I haven't checked, that the spare is the same diameter as a regular wheel, it's only smaller width-wise. So it shouldn't cause any problems.

Reply to
Paul Pedersen

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