I have an '05 Expy 4x4 and am wondering if A4WD affects gas mileage. I have it set to A4WD eventhough I've been doing mostly city driving. Will this affect gas mileage and should I use 2WD in the city?

Also, will the advancetrac be able to still utilize all 4 wheels when in 2WD or will it only use the rear in 2WD and the 4 in A4WD? I read it can transfer to any wheel but wasn't sure if that's only in A4WD.

Thanks.

 

It is my understanding that when in A4WD it only uses the rear axle, until it senses slipping. There was another user on here who tracked his mpg with the A4WD on and off (pulled the fuse) and it didn't seem to make much difference.

As far as which axles get used, in 2wd, only the rear gets power. In A4WD the rear gets power most of the time, but when the computer senses slipping it transfers power to the front.

 

I am not sure if the A4WD has anything to do with gas milage, but I have a friend that has a 99 EXPY XLT that is A4WD and he is only getting 8-9 MPG. I have a 97 ECPY EB and in 2WD i am getting 13.5-14 MPG. It would appear by that it is somewhat of a factor. I am sure driving is more of a factor, but you will have to make that call.

 

So if that's the case than it does make sense to leave it in A4WD all the time. No gas mileage penalty (which makes sense since it's called Automatic 4WD) and use of all wheels for the advancetrac.

I keep reading about pulling the fuse. Did the older Expies not have a 2WD switch position? My '05 has it.

 

No in some of the 99-03/04 we have a switch from Auto 4wd, 4WD hi, and 4WD low

 

So what's with the fuse reference I keep reading about?

 

Correct. My '99 only has A4WD - 4hi - 4lo.

Pulling a certain fuse (Do a search, I can't remember which one) effectivly disables the A4WD by disconnecting the computer that senses slipping. It basically gives you 2wd when in the A4wd setting, but you still have 4hi and lo. If you have a 2wd setting, then you don't need to worry about it because you already have that mode available.

As far as which mode to run in normally. It's kinda up to you. I have no choice so I'm stuck in A4WD all the time. IF I had a choice I would probably leave it in 2wd most of the time and maybe switch over to A4wd if it's raining heavily (and I mean HEAVY) or in light snow.

 

I have an 04 XLT 4x4 with AdvanceTrac, and I only use A4WD in light snow when traction is still pretty good, or when the roads have been plowed. But when the snow is heavier and the roads are still covered, I put it in 4WD Hi.