Four Wheel Drive Low Range failure

[Jon Burns]

Hi Guys,

I really could use some help with this. I have searched extensively but just can't find anything which helps with this problem.

I have a standard 1997 sohc 4.0 liter Explorer in RHD which is as far as equipment levels go somewhere between an LTD and an Eddie Bauer, I think. I recently replaced the magnetic sensors on the transfer box that determine front and rear axle speed as well as the transfer case switch motor. This was because the car would not engage 4WD and would only run in 2WD. We can now get the car to select Auto and 4x4 Hi but it will not select 4x4 Lo under any circumstances. Worse if you try the system goes haywire and you have to stop the car and disconnect the battery for a period. On reconnection all is well so long as no attempt is made to select low range. When the car malfunctions the 4x4 lights on the dash flash 5 or 6 times every couple of minutes.

I love my Explorer and I'm trying desperately to solve this rather than junk it and buy a Merc or something Japanese. I'd be really grateful if anyone has an idea about this.

 

[janolsson]

Hi Jon
I have a transfer case sat in my garage off a 97 box (i think as it has the sensor on it). It came off a tranny that i got off chrisq and was sold as a working unit. Also has the motor on it.
I'm in Leicester if your interested make me an offer !!!

 

[IZwack]

Dont worry about 4LO. In my opinion, 4LO just gets people in trouble - such as when a vehicle wont come out of 4LO so the driver is forced to drive home at 35 mph and 4,500 RPM. 4LO provides more torque and unless you are climbing steep inclines where the tires can acquire 100% traction (rocks, asphalt, etc..), then you dont really need the extra torque. If I were you, I would just settle for 4HI and not even worry about the LO range.

 

[Jon Burns]

Janolsson,

Thanks, I'm not at the stage yet where I want to drop the transfer box but that could change rapidly. PM to follow.

IZwack,

Yeah I'd already come to that conclusion but I would like the thing to work right and I'm not keen on swapping out the transfer case if it won't cure the problem. But disabling 4Lo buy cutting a wire at the switch may be the answer. That way an accidental move of the selector switch won't disable the vehicle. Assuming that doing that won't cause more problems.

Thank you both for the input.

Any one else got an idea about this?

 

[bluestream1]

I am sure you know this, but Gear shift must be in Neutral to get in to 4LO

 

[Jon Burns]

Yes you are correct I do know this but all that happens is that the flashing lights appear on the dash, the car will not engage 4Lo and then will not engage either 4 Hi or Auto. So it's up with the bonnet/hood and time for a battery disconnect. Okay it will drive in 2WD but it's not a fun experience and if it were to happen when you really need 4x4 then
things could get really unpleasant.

Hey but thanks for the input, I might not have known about selecting neutral.

 

[bluestream1]

Have you checked the plug that connects to the back of the 4x4 selection switch? Also what about the wireing going to the transfer case?

 

[Markn]

Jon
Have the same problem you had ie, only 2wd.Selector appears to be OK and 4wd high and low lights appear on the dash.Have read more threads than I care to remember but my biggest problem is to isolate whether it's an electronic/electric fault or is the TC shot.
It would be much appreciated if you could give me a "how to " on replacing the magnetic ( Hall!!) sensors and the TC switch motor.
Btw my Ex is also a RHD 97 xlt.

 

[Jon Burns]

bluestream1,

Yes all the wiring checks out OK and I'm going to be picking up a t/c this week in case it is shot. I was also thinking it could be the unit that controls the 4x4 that lives behind the dash, dunno what it's called but I believe it's there somewhere.

Markn,

I haven't done this myself but as I understand it it's not too difficult the sensors are a push fit just need a little wiggling to get them free, although I think one is located to the rear of the switch motor, but it's only on three bolts. Otherwise to work out whether it's a mechanical or an electrical problem is really above my pay grade. I assume it's like anything else you just have to work thru it all in a logical sequence. but then what do I know LOL.

 

[Markn]

Thanks
Will continue searching although the big problem in South Africa is that Ex's are extremely thin on the ground as are technicians to work on them.Ford only sold a limited number back in 97/98 and whilst they still have some spares in stock most have to be imported from the States or Australia.
Have read Glacier911's 4405 TC rebuild diary,an excellent article,but connot see myself attempting the rebuild as this requires specialist knowledge and the spares question will keep me off the road for weeks.
The unit that controls the 4 x4 operation is the GEM and it lives behind the radio which you have to remove to access it and ( I'm open to correction ) the TC relay.Again there are a number of good threads dealing with this issue but my knowledge of auto electrics is very basic !!!!

 

[Jon Burns]

Sorry

Sorry it's taken so long to come back on this. I've been busy the last couple of weeks. I've managed to pick up a complete T/C out of a '97 X (Many thanks to janolsson) and I'm waiting for my workshop to fit it and then we may discover if the GEM needs swapping out. Hopefully we're getting to bottom of this riddle. We shall see.

 

[Jon Burns]

Update

Well I have managed to get the X back to where it was before I had the latest troubles with the 4x4. Now to stop the flashing lights appearing I'm back to starting the car with the selector switch set to 4x4hi. Then before moving off I set the switch to Auto and the car drives and functions as normal.
I can select 4x4hi and 4x4Lo and they engage normally and actually work.

As we've only changed the transfer switch motor and sensors (but not the actual transfer case) this makes me think that the GEM unit is the most likely culprit. So that's the next step. If that doesn't cure the fault then we'll swap out the t/c and see where that goes.

If anyone has any comment to make please feel free to add your two'pennerth (two pence or cents worth).

And thanks again to all of you out there who are helping to keep my X where it belongs - on the road.

 

[janolsson]

Jon
Surely in a workshop with a lift, swapping out the tc would only take half hour. I imagine getting to the GEM would be harder. You could do the quick swap and if it works then do the fluid service.
As you have the tc it's worth trying that before you fork out for a GEM.
there you go thats my heipenny.

 

[Jon Burns]

Well, you are surely right, however I think that my workshop guys are suffering from Explorer fatigue. They got the system to work, rang me and said it's done come and get it. I didn't actually see them dancing a jig (kinda like Bruce Willis at the end of The Last Boy Scout) but there was a distinct hint of irish flute in the air. Of course what had happened was that if you start the car in auto 4 times out of 5 the fault appears so you know it's broken. But they lucked upon the 1 in 5 times that it works correctly so having had it up on their ramp for months they have got me "beta testing" the thing "to let it settle down". Or as the Colonel in Mash would say "Horse Puckey! Anyway I've just put a couple of hundred miles on the car, needless to say it runs like it used to so I'm going to see if I can find a GEM and try one. One thing they did do was check the fluid level in the T/C and it was OK. And as they haven't asked for any payment, yet, I guess I'm ahead of the game.