hello. I have a 2000 excursion v10 with 66k miles on it. this past weekend i went to engage my 4wd and it would not work. the light on the dash is on and i think i heard a click but no luck. i am curious what people think. a buddy told me to tap the transfer case motor with a hammer but am a little skeptical. another friend told me to check the vacuum switch with the vent/ defroster but i am not sure that holds true with my yr/model (i did a test where i left the vent setting on face/feet then turned on the 4wd. the airflow seemed to remain as set). anyone here have this problem or some advice for a medium level do it yourselfer? fwiw... about a year ago i removed, regreased and repacked my front hubs.

 

Does 4x4 work when the hubs are in the locked position? If so it is probably a vacuum issue when the hubs won't engage in the "auto" position

Clockwise to lock

 

the hubs are on "auto" and the 4wd was working just a few days prior.

 

if the answer to that question is no (i wont know until i can test tomorrow night), would that mean it would have to be solenoid or tfxr case motor?

 

does your heat come through the center vents when its set to console?

I had to replace the solenoid, its cheap less than $40. Also check the condition of the vacuum hoses going to the hubs.

Otherwise just use the manual setting on the hubs.

 

yes, as i mentioned, i tested the face/feet setting on the heater vent. the air blows thru the face/feet vents in both 2wd and 4wd. the 4wd indicator also works

 

sorry I missed that, this is probably what you need and also maybe vacuum hoses- its possible one has slipped off or just deteriorated. Just because the 4x4 illuminates only means the transfer case is engaged- if your hubs are not you don't have 4wd


5 minute install.

 

If you light is on, You here the clunk, If you did not, put in low, then CLUNK should be heard. If yes then is not the shift motor SO put your hammer away & lock in the hubs by hand. 99.9% chance you'll be in 4X4 at that point.

 

I have the same issue. I can lock it in manually but auto doesn't work. I have a very large vacuum leak as my hose is no longer existent on passenger side.

 

thanks everyone, i am going to try and run some tests tonight or over the weekend depending on time. my plan is to:

- recheck the vents to insure vacuum pump is working
- turn on 4wd to listen for a clunk to rule out txfr case motor
- flip hubs manually and check 4wd funct. to rule out vacuum leak.

if at that point everything is functioning, i will replace the 4wd locking solenoid.

do i have this right? any other suggestions? Are the 2 solenoids identical? i just saw a video that said if you are changing 1 you should do both. are they different parts? interchangeable? thanks again to EVERYONE who replied thus far. the help is GREATLY appreciated!

 

I hope your vacuum pump is working, if it isn't then it doesn't matter if the 4X4 systems works or not.
Your EX has a V-10, so the engine is your vacuum pump. . Diesels have to use vacuum pumps because they don't have engine vacuum like the gassers do.

Turn the dash **** all the way to LOW range to verify the shift motor is working, you should be able to feel the difference in gear ratio in LOW pretty quickly.
With the truck in 4X4 and driven for a short trip with the hubs in Auto park it and leave it set to 4 High. Then get out and reach around behind the front tires and try to spin the steering knuckle U joints. If they spin your hubs are not locking in Auto, if you can't spin they are locking in.
If they are not auto locking in then check the vacuum switch under the hood on the right fender, it should be pulsing vacuum on the outlet port that goes towards the front hubs when you are in 4 high or low. If it isn't sending the pulses it is possibly failed, if it is sending the pulses and the hubs do not lock then check all along the tubing/hose path for a break, leak, disconnected or crumbling hose. If all of that is good it might just be time to pull, clean, service and reinstall the hubs.