Is My Truck Stuck In 4x4

[seanosborne]

Okay, a little background info. It is a 98 explorer with the Control Trac transfer case, so the selector switch has the Auto/4 High/4 Low settings on it. AND i just got a brand spankin new tcase shift motor installed before today there was no shift motor so it was a full time 2WD.

I got it installed because there is a lot of snow and ice on the roads right now.....but heres the thing, when i gun it in a straight line, or even around corners i get tons of traction even on ice. Now this is a good thing because before today i would have been slipping and sliding all over the place.

BUT is this system suposed to work that well in the AUTO mode? I mean, shouldnt there be some sort of response time? the sensors first have to detects that the back tires are spinning faster than the front ones, then engage the transfer case clutch.......but i dont really feel any rear tire slippage and my back end doesnt come loose before the 4x4 is engaged....

So i am wondering if the system is really in auto mode, because after driving in the snow and ice in both AUTO and 4 HIGH, i cannot feel any difference.

Also IF it is, for some reason, in 4 HIGH, is this a cause for imediate concern? I have read some posts that state VERY strongly that 4 HIGH should only be engaged when needed, and NEVER used on dry or even wet pavement. But I have Also read that although that is very true for almost all other 4x4 systems, this peticular breed of vehicle can be driven in 4 HIGH without causing any problems.

So, my questions are:
1) HOW can I tell if my truck is stuck in 4HIGH?
2) WHAT would cause this to happen?
3) Will driving it cause any damage if it is?

PS, when the switch is changed from 4HIGH to AUTO, The 4HIGH light on my dash DOES turn off

 

[zonianbrat]

Okay, a little background info. It is a 98 explorer with the Control Trac transfer case, so the selector switch has the Auto/4 High/4 Low settings on it. AND i just got a brand spankin new tcase shift motor installed before today there was no shift motor so it was a full time 2WD.

I got it installed because there is a lot of snow and ice on the roads right now.....but heres the thing, when i gun it in a straight line, or even around corners i get tons of traction even on ice. Now this is a good thing because before today i would have been slipping and sliding all over the place.

BUT is this system suposed to work that well in the AUTO mode? I mean, shouldnt there be some sort of response time? the sensors first have to detects that the back tires are spinning faster than the front ones, then engage the transfer case clutch.......but i dont really feel any rear tire slippage and my back end doesnt come loose before the 4x4 is engaged....

So i am wondering if the system is really in auto mode, because after driving in the snow and ice in both AUTO and 4 HIGH, i cannot feel any difference.

Also IF it is, for some reason, in 4 HIGH, is this a cause for imediate concern? I have read some posts that state VERY strongly that 4 HIGH should only be engaged when needed, and NEVER used on dry or even wet pavement. But I have Also read that although that is very true for almost all other 4x4 systems, this peticular breed of vehicle can be driven in 4 HIGH without causing any problems.

So, my questions are:
1) HOW can I tell if my truck is stuck in 4HIGH?
2) WHAT would cause this to happen?
3) Will driving it cause any damage if it is?

PS, when the switch is changed from 4HIGH to AUTO, The 4HIGH light on my dash DOES turn off

1. If you wondering if the auto 4x4 is stuck in 4high then take a tight turn on dry pavement going really slow if you in 4high you will feel the drive line bind because the tires will be turning at different speeds. If it turns smooth then your ok.

2.Not a expert by any means at all but since it is a computer/electrical controlled system there could be a fault somewhere. Do any of your 4x4 buttons blink? If so that means that there is something wrong and you need to have the codes pulled.

3. Yes this 4x4 system will be damaged if in fact you are stuck in 4x4 high and your driving on high traction surfaces

As far as the auto 4x4 goes I did some adventuring today and I know what you mean I think the system must engage pretty darn quick. I floored it in some snow today and it spun maybe for a second then it jerked when the system kicked in. Hope this helps but remember I am no expert and I just got my X a few months ago. I am still learning about the true trac system myself. I am used to having manual shift 4x4.

 

[gijoecam]

If you floor it, the system will lock the t-case before the rear wheels break traction. The system uses more than just the wheel speeds to calculate transfer case duty cycle... It also uses vehicle speed, engine RPM, load, and throttle position to modulate the duty cycle as it sees fit.

It should never spin the rear wheels for a second before engaging the fronts... if it ever does that, then there's something wrong.

-Joe

 

[seanosborne]

wel, it certainly sounds like Fords Conrtol Trac system is more efficient than i though it was.

Like i said, when driving on snow and ice. I felt no difference between the AUTO and 4 HIGH modes, and i thought this was strange.

But just to be sure, i will try taking a tight turn on dry pavement......

Also i have a follow up question. I have read some posts that state that when in AUTO mode and the tranfer case engages the 4x4, it is fully engaged. That is to say, there is no in between, it is either on or off.
I have also read some posts that say the tcase clutch can be engaged 10%-100% depending on conditions. So which one is it?

 

[gijoecam]

Both.

There's some debate on that one.... I've not been able to ascertain anything concrete one way or the other.... As far as I can tell from a mechanical standpoint, I can't see any effective way where the transfer case could be anywhere between fully locked and fully unlocked. Either it's sending torque to the front axle, or it isn't.

However... Admittedly, I've never had one apart, and never played with one on a bench connected to a proper pulse-width modulated signal as it would in the vehicle. While it's obvious to anyone that's used a lighted switch with the brown wire mod that the control system varies the current to the clutch coil, it's not mechanically apparent how that variation in current affects the torque split. (again, it may become apparent to me if I'm ever able to open one up on a bench)

So, I really can't give you a definitive answer one way or the other.

 

[buck1946]

Mine is stuck in 4W High too. Can I disable 4W?

My 99 XLT seems stuck in 4WD High. It bucks on dry pavement and shudders on turns and there is no noticable change in sound or driving characteristics when I shift between 4W AUTO and 4W HIGH. ( I have never used 4W LO ).

The local Ford dealer service Dept. returned the car to me as OK, and now I am stuck here in Cincinnati till I can get them to look at it after the weekend.

My question is, Can I pull a fuse or relay from a readily accessible spot to disable the 4WD altogether? I need to make a 1200 mile trip NOW. I have read the Brown Wire Mod. and don't really want to go to that much work.

Or, is it likely a mechanical issue of the transfer case being stuck. I will try tomorrow to disengage in neutral. I did drive the car in 4WD HIGH recently on snow packed Interstate for about 100 miles at around 45 mph. (I also drove about 4 miles with the parking brake on hard. The loss of 2WD seemed to occur at that time.)

I'm not sure my 99 has any lights on the 4WD switch.

So, what I'm looking for is a way to take a highway trip without tearing up my tires or drive train. Otherwise, I'm stuck in 4WD and stuck in Cincinnati!

Thanks in advance.

 

[gijoecam]

The quick, simple, dirty way to determine if it's mechanical or electrical: Crawl underneath the truck and unplug the connector at the transfer case. It's right near the transfer case shift motor. Then do some tight turns on dry pavement. If the driveline bind-up persists, there's a mechanical issue with the t-case. If the bind-up goes away, we know it's an electrical gremlin in the control system.

I would expect that there would be no difference in the sound between 4high and 4low. The only thing that changes is the t-case will lock up. All the front drivetrain components are always turning.

Good luck!

 

[buck1946]

Thanks GI! I will get out and try that today.

I was always able to hear a difference between AUTO and HIGH, but only on dry pavement. It was a sort of gear whine, probably due to the tension from front vs rear. (But then I do have quite good hearing even at 62.)

I actually don't hear the whine now, but the gears may have worn in on the 100 miles of snow packed Interstate in HIGH.

Anyway, I will post the results of my efforts to get it going.