Flashing 4WD / $WD Lo lights and "clunk" up front!

[Cheddarhead]

'97 XLT with the 4.0L engine and the "control Trac" 4WD system...

Just flushed the transmission, changed the filter, and re-filled the tranny.

My son reported that the 4WD and 4WD Lo idiot lights came on when he was driving at Highway speeds. They would flash 6 times...then stop. Would begin again after 2 minutes.

He also noted that the right rear tire was very low....20 - 24 PSI. Tire has a slow leak, and was likely driven in this condition for up to 100 miles.

I drove the truck approximately 10 miles...felt a "binding" in the steering / front axle. Especially when making a low speed LH turn (parking lot).

Ideas? I'm 1,000 miles away (now) and can't pull codes until I return in a couple of weeks....but I'm concerned that running the truck with a low tire may have damaged the driveline.

Thanks in advance!

 

[badgett]

Disconnect battery. Remove both speed sensors. One by each driveshaft on transfer case. Clean crap off the speed sensors and put them back in. It worked for me 4 years ago and still no more blinks.

 

[Cheddarhead]

Disconnect battery. Remove both speed sensors. One by each driveshaft on transfer case. Clean crap off the speed sensors and put them back in.

Thanks for the response. I can have the battery disconnected now, so everything will be ready when i return this weekend. I've ordered the service manual from amazon...but in the off chance that it does not arrive in time for me to use it this weekend, A couple of follow-up questions...
1. Where do I find the speed sensors referred-to above?
2. Do I need any special tools to remove / reinstall these?
3. Any special cleaners needed...or will a typical electrical / electronic contact cleaner suffice?

Again...thanks in advance!

Charlie

 

[badgett]

Look under the truck where the transfer case is. There is a little black sensor with one bolt holding it in right where the driveshafts come out of the transfer case. One for each driveshaft. The wiring harness goes back to the shift motor. All they are really is electromagnets. The crud that builds up on them keeps the magnet from working. I just sprayed them off with brake cleaner but some say that is too strong. It didn't hurt mine.