98 "Auto" 4WD lights flashing on dash

[rlhack]

My 1998 4WD (4.0, SOHC engine, 5 spd automatic) has the auto-4WD transmission. With 83,000 miles, the vehicle has operated reasonably well to this point. However, today while driving on dry streets, the dash lights that show "4WD high" and "4WD low" began to intermittently flash, sometimes alternating bethween the two, sometimes simultaneously and then would go out for a time period. The lights even flashed when the car was parked with the engine rounning. The vehicle continued to move and I got it home (short drive about 10 miles) but performance was noticeably more sluggish. Does anyone have an idea of what is happening? Is the transmission shifting into and out-of 4WD; or is this just a quirky short? (I would expect the former given the poorer performance). Right now, the car is dead in the water, not wanting to risk any transmission damage.

 

[caldi55]

That happens on mine also, its going into the shop tommorow ill let you know the outcome

 

[Blee1099]

Do a search on flashing 4wd lights.. You'll get alot of info on it. Most times, its the shift motor thats needs to be cleaned but it can also be the hall sensor and other sensors.

 

[rlhack]

THanks for the quick guide/tips. I did the search as suggested and it seems to indicate that either the speed sensors or the shift motor. I would tend to not think the latter since the car has not been on anything other than street pavement for the last 6+ months. Nevertheless, the guidance is terrific and it will give me some ammunition when I try to get it serviced.

Thanks. Any additional input is appreciated. Great Web site and information forum!!

 

[paul99explorer]

Mine started flashing a while back, but I didn't really notice any performance issues. It was like that for a few weeks until I cleaned my MAF sensor. After cleaning it, I unplugged the neg. battery terminal for about 20 minutes to reset the ECU. The lights haven't been back on since. Just thought I would throw that out there.

 

[Bandido]

refreshening this thread... PLEASE Help

ok, just a quick question to the same topic.
I know I should search, but I am on a weekend trip and am sitting in a hotel right now...

I also had this 6-times flashing of 4x4High and 4x4Low. It suddenly came on after 5 hours Highway driving! 4x4 doesn't engage anymore or at least the light in the dash doesn't come on. You can hear clicking and when you shift into low or back, it kinda clunks sometimes in the drivetrain.
Can I drive the X home the 500miles on Sun??? Or should I try to get something fixed tomorrow morning? As far as I can find a shop open...

Thanks, I really appreciate any answer...

 

[TPLYNCH]

It's a little late, but if you haven't yet, try resetting the computer by disconnecting the battery for 15-30 minutes. You should be able to drive, as long as you don't feel the front end binding when you are making sharp turns etc.

 

[Bandido]

thanks tplynch, yeah it is a little late. I am already back home... The lights stopped flashing the next day.
When I drove home on Sun after 1 hour of Highway driving they started flashing again! But I drove home and this morning on my way to work they didn't flash. So it must have something to do with the highway driving (70-80mph)

Maybe some sensor or the not enough fluid or so? I gotta check that later. But now, when the lights are not flashing I can shift into 4x4 high and low.
When the lights were flashing, it clicked but didn't engage in either one...

 

[TPLYNCH]

The sequence of the flashes indicates the problem code. 6 flashes, repeated every minute or so is an indication of speed sensor issue for example. I'd check the simple stuff first, connections/fluid level etc., then see what happens.

 

[Bandido]

so if a sensor is broke, I can't shift into 4x4? What exactly does the sensor sense? I mean it is called speed sensor, but what speed does it note?

 

[TPLYNCH]

It measures the difference in speed between the front drive axle and the rear axle. If they sense to great a difference in axle speed (tires spinning in rear), the GEM knows to apply the clutch in the T/F case to send power to the front wheels until the axle speeds are the same, then it disengages power to the front unless it senses differences in axle speeds, at which point it would apply power to the front again. That's how the Auto 4x4 works. In Hi, the clutch is locked so that 50% power goes to front and back. In Low, there is an actual shift into a reduced gearing. The clutch is not engaged. Depending on what codes the case is throwing, it may not allow 4x4 to engage if doing so could cause damage to the system.

 

[Bandido]

I know this is the 911 Forum, but thanks for clearing that!!

 

[cindeelou]

I am having the same problem, it happened after I had my lower ball joints replaced ( coincidental??) But when it is in 4wd and turning it really binds up and makes a horrible noises.....what is it doing and why???

 

[TPLYNCH]

Cindee, exactly which 4x4 are you in when it does this.... Auto, 4Hi or 4Low? If 4Hi or Low, if you are driving on pavement, it will bind and make all sorts of nasty noises. Hi and Low should not be used on pavement or non slippery surfaces.

 

[dickypooh]

anybody help me my 98 ex 4wd hi 4wd lo started flashing and wont go in 4wd just hindin spins any thoughts