should I feel the difference between the 2WD & auto ?

[hangout]

I just bought the 2001 QX4 two months ago.
this is first real 4WD truck I have, FX35 is a crossover

I like this QX a lot. since I am new to the 4WD, I have a stupid question.
when I drive the QX in 2WD or auto mode, I really can feel the difference between them. But, in the AUTO mode, the QX should running rear wheel most of the time, only 4wd kick in whenever the computer detected the slip, right?
if what I think is true, then why I can feel the difference while I drive in different modes?

is this normal, or just me?

[iceman14n]

i use the truck in the snow mostly so i dont feel the difference between 4WD and Auto.... where as your case is different.

In Auto, you should be on RWD (2WD) most of the time, but soon as the wheels start losing traction then the system transfers 50% of the power to front making it a 4WD.

I dont feel the difference between 4H and Auto but i do see the 2WD and Auto Gas Mileage is very very close for me, but as soon as i put in 4H, then i see the Gas mileage drop drastically.

Hope that helps!!!

[fleurys]

Like iceman said, you will not feel the difference between 2h and auto simply because there is no difference what so ever UNTIL you get some wheel spin... Then and only then will the transfer case lock the front. Then at that point you will be like 4hi. It will stay like this for a good period of time, at least 1 minute if i remember correctly even after there is no more wheel spin...

[donald]

+1 to all the comments above.
The difference you feel might be psychological.

and just for fun, an expereiment:
You can test this by having covering your switch, and having a family member/friend switch it between "2wd" and "auto" before you drive to work/shopping/errands/etc. Keep it covered and NEVER look at it.
Jot down what you thought it was set in (ie. 2wd or auto) and compare with what your family/friend had set it as on that day.

Putting it in auto while driving in the city shouldn't hurt the drivetrain - at least I wouldn't think so.

Otherwise, if you ARE feeling a true difference and it's not psychological, then based on the concept that power is delivered to the front's when there is slipping in the rear, then there might be something wrong with the sensors and it's erroneously sending signal to power the fronts.

(mind you I'm no mechanic - I'm only speculating and trying to make logic out of your description)

[ARKQX33V6]

Driving in 2WD and in Auto, where the vehicle gets 4WD when slippage, you should feel the difference especially in slippery conditions.

But even on dry roads there is a noticeable difference for 2WD to Auto and then back to 2 WD

The car seems to tighten up. In these wet slippery Canadian roads with black ice and crowned roads the steering is sensitive and with 4 wheel snow tires I know I can feel the car. Now it's a 97 the first QX4 and there may be advances in the newer cars, but from what I see here the 01's seem to have there share of breakdowns. I don't know maybe those owners can chime in or it's just a matter of more 01's than 97's

Try out your Q for control by going through the gears in an automatic set in D with transmission warmed. The overdrive on. A very gentle throttle is needed on 2 lane roads from 0-90 km/hr or 0-55 mph. Can you keep it below 2000 RPM, can you notice converter lock up and release? Try it, be sure no traffic, try it with hills and flat. If your revs seem high what is your lowest RPM at any and all shifts. Can you drive it into top gear at 1000 RPM. Control? Transmission problems? Action vs. reaction? RPM vary or steady?

[Buzzman]

I have a 2002, and I can honestly say I don't notice a difference between 2WD and Auto. In my neck of the woods, I drive in snowy weather 4 months a year, and constantly switch back and forth between 2WD and Auto....almost always while moving no less. Unless the front wheels engage in slippery conditions, it feels exactly the same. I've gone on the freeway numerous times, and at 120-130 Kms/hr., looked down at the dial and realized I was still in Auto mode. I've switched it back to 2WD at those speeds with no ill effect. However, I do notice a difference when going in 4WD Hi. The truck definitely seems to labour more in 4WD, so I rarely use it.

[yeldogt]

Buzzman -- all you are doing when you place it in 2wd is stopping it from automatically moving into 4wd in a slip situation. On dry pavement it is not going to operate any differently in auto or in 2wd because even in auto the truck is never going to move into 4wd -- its in 2wd. The auto is just an "on" switch to allow the electric transfer-case to move to 4wd. when it starts to slip in the rear. Mine is always in auto

[Buzzman]

Buzzman -- all you are doing when you place it in 2wd is stopping it from automatically moving into 4wd in a slip situation. On dry pavement it is not going to operate any differently in auto or in 2wd because even in auto the truck is never going to move into 4wd -- its in 2wd. The auto is just an "on" switch to allow the electric transfer-case to move to 4wd. when it starts to slip in the rear. Mine is always in auto

I understand perfectly well how it works. However, in the opening post from the author, (hangout), he stated that he felt a difference from 2WD to Auto, and was asking if anyone else felt the same thing.
That's what I was responding to. Thanks for the lesson though.

[iceman14n]

another thing which is very important to note is that in 4WD, not matter Auto or 4H, if the 4WD is engaged, then at about 110-120Km/h and up, you will feel a little, very minor grinding on the gas peddle. this is normal for any truck with this option that this SUV has.

This can be another check of whether the front wheels are locked or not.

I just wish that on the cute little 4WD digram in the dash, it would show if the front wheels are engaged or not in Auto mode,

[hangout]

actually, while I drive it in the 2WD, the truck feels lighter, and easier to do the cornering.
if drive in the AUTO mode, I feel the truck is tighten.

[yeldogt]

I agree it would be nice if the system told you when it was switching into 4wd - similar to cars telling you when the traction or stability control is activated - the light would alert you to an odd slippery situation. I don't know why you would not want to keep the system in "Auto" - You get the benefit of the 4wd system when you need it? The way it is set up it quickly goes back to 2wd - the running costs are almost nothing?

While its not a very sophisticated 4wd system --- the electric transfer case is extremely smooth.