Hey Guys, i posted this over in the expedition forum, and was told to check this board out, can anyone help? i've read some of the messages, but they seem to be concerened with the 4wd not disengaging, mine does that no problem, heres myu problem, copied from my original message on the other board.


and i posted this later:


any help would be greatly appreciated!!!

 

Here is my suggestion: Take the truck in the loose stuff and see if the front wheels are engaged in 4wd. e.g. mud, snow, gravel, dirt. Drive the truck in 4WH in circles and if it is alternately easier and harder to turn then the front tires are getting power intermittently and you have a problem. There should be a big difference in turning ease when 4wd is engaged or not.
-tom

 

Hey, I get the same exact thing in my '98 Expy. When in 4WDH it will occasionally click back and forth from 4WDH and A4WD. Same thing, too, it will happen a couple of times within about 10 seconds and then won't happen again for a few minutes and sometimes longer. I do believe I posted about it in here probably over a year ago and never got to the bottom of it. BTW, I assume your drive selection dial is: 2WD-A4WD-4WDHI-4WDLO, right?

My vacuum motor on the front differential went bad and was replaced. This fixed the problem with the front wheels not engaging but the back/forth from AWD and 4WD still happens. I also replaced the vacuum lines from the solenoids to the vacuum motor so I'm pretty sure it has nothing to do with that.

If you ever get to the bottom of it please let me know.

Also, when in A4WD or 4WD, does the front end make a grinding type of noise? (And maybe even some whining?) When I click it into A4WD and give it some gas it seems to catch/release/catch and make some funky sounds. Regular 4WDHI doesn't sound as loud and doesn't catch/release/catch, although there is no mistaking that it's engaged just by the noise. It's makes less 'grinding' noise than AWD but still does have a whine to it. Just mine or no?

FYI, the history of my front-end is as follows:
- About a year after buying it new I noticed a small leak coming from the front differential around the pumpkin. Ford fixed under warranty. (Wasn't leaking enough to drip on the garage floor - noticed it when changing oil)
- Every time I drove it in the snow since new I noticed the back/forth from AWD/4WD.
- Vacuum motor on differential was replaced because although the transfer case engaged, the front wheels would not get power in 4WD/AWD. Noticed this last winter and hadn't fixed it until this past summer.
- As far as I can remember the front end always had some grinding noise to it. Don't think it was harmed by the leak as I said it wasn't even bad enough (and didn't happen long enough) to leave a stain on the ground. I haven't checked the fluid level although I'm sure I should.

Anyways, if you do find the cause please post up!

 

I have more "noise" from my front end when it is A4wd. This is before it detects any wheels slipping. I have no idea why...

 

Any ideas?

 

This sounds like the Transfer Case motor contacts are going bad. There is a TSB on this.

Ian