Is 4X4 Auto same as AWD?

[steven7todd]

The tire shop people are telling me that 4X4 Auto means that it's AWD and the manual simply says that 4X4 Auto has power going to all the wheels.....thus I need to replace all four tires at once. But I've heard from a handful of others that 4X4 Auto means that it normally operates in 2 wheel drive but when the vehicle senses sufficient rear wheel slippage it automatically kicks into 4 wheel drive which obviously is very different than AWD.

 

[RangRayy]

thats how my 99 is AUTO HIGH and LOW. Auto just simply means when the conditions are right and the rear tires slip the transfer case engages kicking in 4x4. once the slipping stops it usually disengages. thats what i have been told and experieinced with my auto switch. so no auto does not mean AWD. it would say AWD instead of AUTO if so.

 

[SpartanTS]

You won't have to replace all 4 tires because the 4WD system isn't permanently engaged. For example, my Jaguar has AWD witha 40/60 power split, so whenever I need a tire/tires, I have to replace them all.

In your case, the system isn't permanently engaged, so you don't need 4 tires since the power is only re-routed when the car detects slippage, which I can imagine isn't very often.

Don't let those guys screw you over, because they'll try. Buy two tires, rotate the others, call it a day.

 

[Hitchhikingmike]

On the other hand, would the 4x4 auto system kick in more frequently if you did not replace all 4 tires because there is a slight circumference difference and the computer can sometimes mistake this for rear wheel slippage?

 

[SpartanTS]

On the other hand, would the 4x4 auto system kick in more frequently if you did not replace all 4 tires because there is a slight circumference difference and the computer can sometimes mistake this for rear wheel slippage?

Unless you're doing jack-rabbit take off's or burnouts on a regular basis, the Auto 4x4 system isn't going to kick in, especially during normal driving. The T-case isn't that sensitive to detect such a small difference in tire wear.

With my Jaguar, I can count the times that the AWD system has kicked in. Most of those times, I've induced the slippage by having a little fun in the rain dropping the clutch

So in a word, nope.

 

[joecrna]

If you use the same size and brand, then it is unlikely to cause a problem. Even if they are different brands but of the same exact size, it should be OK. However, many people have premenantly damaged Transfer Cases by running mismatched tires front and rear. A good rule of thumb is if you would use the different tires on opposite sides of your vehicle and not worry about damaging a limited slip differential, they should be OK to use on opposite ends of your Explorer. Our trucks measure wheel speed at several different points including inside the TC itself. They don't require much difference in wheel speed to lock the TC.

 

[steven7todd]

I'm getting a "Tire Sensor Fault" every time I start the vehicle now which makes sense because I have the spare on. I've actually been getting this message for a month or so now. Nonetheless, I wonder if this impacts whether or not the vehicle allows the TC to lock.

 

[blueka]

Unless you're doing jack-rabbit take off's or burnouts on a regular basis, the Auto 4x4 system isn't going to kick in, especially during normal driving. The T-case isn't that sensitive to detect such a small difference in tire wear.

With my Jaguar, I can count the times that the AWD system has kicked in. Most of those times, I've induced the slippage by having a little fun in the rain dropping the clutch

So in a word, nope.

your jaguar runs the same AWD system as my Mondeo (US Contour), it's quite a clever set up, needs more grunt though.


Si

 

[SpartanTS]

your jaguar runs the same AWD system as my Mondeo (US Contour), it's quite a clever set up, needs more grunt though.


Si

I have the 5-Speed Manual with my X-Type (somewhat rare from what I hear), which actually gives the car a lot more giddy-up than the automatic. However, it sure could use more power.

Unfortunately, the transfer case has the strength of a toothpick, so anything over ~260HP and you start to have issues.

 

[blueka]

I have the 5-Speed Manual with my X-Type (somewhat rare from what I hear), which actually gives the car a lot more giddy-up than the automatic. However, it sure could use more power.

Unfortunately, the transfer case has the strength of a toothpick, so anything over ~260HP and you start to have issues.

yeah, mine's a manual too, and only has 136bhp...


Si

 

[IZwack]

You won't have to replace all 4 tires because the 4WD system isn't permanently engaged. For example, my Jaguar has AWD witha 40/60 power split, so whenever I need a tire/tires, I have to replace them all.

This is incorrect -- the system will kick on and we have witnessed this on the forum plenty of times where a mismatched tire caused the system to engage 4wd.

I would replace all four tires at once.

 

[SpartanTS]

This is incorrect -- the system will kick on and we have witnessed this on the forum plenty of times where a mismatched tire caused the system to engage 4wd.

I would replace all four tires at once.

We never said anything about mismatched tires. If there isn't significant tire wear, and being that this is a 4x4 and not AWD, you don't have to replace all 4 tires. However, 2 tires SHOULD be replaced, and they should be the same brand/sizethat you already have.

As I said before, if you're doing normal driving, and I stress normal driving, it's not necessary to replace all 4 tires in his situation because 4x4 systems are not permanently engaged.

 

[SpartanTS]

yeah, mine's a manual too, and only has 136bhp...


Si

I have the 2.5L V6 with 197HP. The AWD system is great from a dead stop, but the weight catches up with her around the middle of 3rd gear and then the pulling stops

 

[IZwack]

We never said anything about mismatched tires. If there isn't significant tire wear, and being that this is a 4x4 and not AWD, you don't have to replace all 4 tires. However, 2 tires SHOULD be replaced, and they should be the same brand/sizethat you already have.

As I said before, if you're doing normal driving, and I stress normal driving, it's not necessary to replace all 4 tires in his situation because 4x4 systems are not permanently engaged.

Sorry, I should have defined "mismatched" -- which means of different diameter.

If the dash has the usual AUTO, 4HI, 4LO options, then the system is always engaged because there is no way to stop it from reading driveshaft velocities other than pulling a fuse, doing the BWM, or the likes.

 

[SpartanTS]

Sorry, I should have defined "mismatched" -- which means of different diameter.

If the dash has the usual AUTO, 4HI, 4LO options, then the system is always engaged because there is no way to stop it from reading driveshaft velocities other than pulling a fuse, doing the BWM, or the likes.

Yeah I should have stated that in the beginning. I think I said it in the other thread he made about his issue.

I was under the impression that the system wasn't engaged until slipping occurs, therefore operating in 4x2 mode otherwise. If that's not the case, and if it's anything like my car, then buying 4 tires is probably not a bad idea.

 

[steven7todd]

I haven't seen the system automatically engage the 4 wheel drive yet on account of the off brand, normal size spare, nor when I was driving on the partial flat. Is it possible that when the car gets a 'Tire Sensor Fault' (which it's been displaying to me on every start up), that the 4X4 Auto system does not engage?