4WD system gone squirrely

[heyjewel]

Today my near perfect 2004 Navigator 4X4 w/143,000 miles started acting up. When I put it in 4 Low and shifted to 2nd (I do this everyday to make descending my steep dirt and rock driveway easier) Nav said it was in 4 Low but it seemed to be in 4High. Raced down the hill. Stopped to take it out of $WD and it seemed to come only halfway out. Front seemed to transfer out but not rear. Took it out on road and it sounded like it was in 4Low yet it was able to move faster than that would have allowed. And speedo said I was doing 80 when I know I wasn't over 25mph. Right now it is stuck in this mode. Tried several times to get it back into normal 2WD but only thing happens is indicator light goes out.

Any ideas for this?

 

[04_Sport_LS]

Possibly a bad electrical "position" sensor in the 4wd,,, but more than likely the glorified power window motor for the "touch drive" 4x4, (if your NAV has that), is starting to take a vaction

 

[heyjewel]

Possibly a bad electrical "position" sensor in the 4wd,,, but more than likely the glorified power window motor for the "touch drive" 4x4, (if your NAV has that), is starting to take a vaction

Mine has the 4 position switch: 2wd, awd, 4high, 4low. Must stop, shift to neutral, step on brake and then turn the switch to 4Low. All other positions are on the fly. All electronics seem to indicate shift to 4Low worked as designed: 4Low light comes on, compressor begins raising the vehicle and I can hear the transfer case motor run but whatever performs the mechanical shift does not work. I think I'm going to pull transfer case motor and see what I can find. Possible some linkage has come loose or broken? Or like you say maybe the motor has waved bye bye. Wish it had not left me in 4Low as it's parting gift.
Thanks for input

 

[04_Sport_LS]

There is probably a gear on that motor,,, that rotates another part to do the actual shifting from high to low. Just a guess,,, but maybe a roll pin sheared... allowing the motor to freewheel without turning the gear.

 

[heyjewel]

I can't find the OBD2 connector on my 2004 Nav. It does not seem to be in the usual place under the dash near the steering wheel. Does anyone know where it is?

Thanks

 

[heyjewel]

Posting info that may help others who knows.
So to investigate my Nav stuck in 4Low, I pulled and inspected and tested the little shift motor and it was OK. Also all lights etc electronics seemed to work as designed. So no choice but to pull the transfer case. It wasnt too bad a job especially since I had a more knowledgeable friend working with me. Complicating matters is that my workshop manual only goes to 2002 and there are differences under the car from my 2004. Prior to 2003 these cars had torsion bars setting suspension height but thankfully none anymore.
So we pulled the TCase and opened it up and the problem was obvious. A 1/8 inch by 5/8 inch by 1 1/2 inch long tab had broken off the gear in the shift cam assembly (item 66 in the parts diagram.) The gear thing on that shaft that broke is cast aluminum. I've found that Ford still sources the part I need out of Detroit for only $120. FordPartsGiant has it for $92.00 Looking for less expensive source. I found that I can get an entire used transfer case for $295 + shipping. Or maybe even at a local boneyard. Dunno if that would be a better idea. It definitely will fix this problem though I don't know if something else binding or ... caused this little tab to break.
We looked around at the TCase (it's a Borg Warner and doesn't seem to have changed from '02 to '04) and it's a beautifully simple machine. A couple of plastic parts, eg shift fork, sortof makes one wonder and this aluminum tab seems a bit too thin and probably breaks a lot but overall a nice unit.
I will post after we get the part and shove the TCase back in. Meanwhile going to change the tranny fluid and filter.

 

[heyjewel]

To finish this story - I got the part I needed from a Ford dealer where a friend works for $92.00 out the door. It took more than a week to get here from Detroit. Good thing I have an LS to drive while Nav was up on jack stands. While waiting for part I drained and changed the transmission fluid and filter. When the new part came in we noticed that the tab which had broken off was slightly more beefy.
My buddy and I put the part in the TC, buttoned it up and shoved it back into place. Loaded it with a smidge over 2 Quarts of Ford transfer case fluid.
Tested TC and Tranny on stands, all OK. Took her for a test ride and runs smooth as new. Gave my helper two crisp $Franklins. Cost me total of $320 or so for what dealer would have no doubt wanted $2000 or more. A win this time.

 

[heyjewel]

There is probably a gear on that motor,,, that rotates another part to do the actual shifting from high to low. Just a guess,,, but maybe a roll pin sheared... allowing the motor to freewheel without turning the gear.

Want to add that you were exactly right - the part which is rotated by that motor was the part that broke. The tab which fits snugly in a slot on the two springs which exert return pressure on the slotted gear in which the shift forks ride is what broke off. So great guessing. You have any similar guesses for the stock market?

 

[04_Sport_LS]

When the new part came in we noticed that the tab which had broken off was slightly more beefy.

And I bet the original part number had been superceeded.

Glad I could help... and this is one more reason why I like all mechanical, (manual), as much as possible when it comes to the driveline of a 4x4 system. When I ordered my '95 new... it got every option but the electronic 4WD. The salesman couldn't believe I didn't want it.

I keep saying my next truck is going to be a '48 Power Wagon.

http://www.legacyclassictrucks.com/images/F145521016.jpg

As far as the stock market... I'm not into that,,, but most of the auto manufacturers are re-tooling right now. Take that for what it's worth.