Ok....will give it a shot this evening when I get to the house. Thanks again for the direction.....

 

If you didn't try the shifting straight to 4x4 low thing, give that a try also. You will see what I was trying to say in my post.

Also, if you ever want to use 4x4 low without having the front hubs lock, disconnecting the solenoid and that will not allow the front hubs to lock. Like backing into a tight spot or up a grade. Will also keep your trans from overheating.

 

If you say your golf tees were seated good when you plugged both lines I would say its a vacuum line somewhere further up from the hubs causing the problem. I was going to replace all of mine but I unhooked all of it and found out it was just fine when I tested it.

 

Ok miller per your instructions, I did this....

--Pulled three prong plug from the PVH solenoid and ran truck switching to 4x4 high. AC did NOT revert to defrost...waited for five minutes just to make sure.

--Ran all new tubing yesterday from frame to hubs

Did golf tee tests today.

--Both sides plugged...4x4 HI ....AC did NOT revert to defrost

--Passenger side plugged/drivers side normal...4x4 Hi on...AC did NOT revert to defrost and axle at ujoint no longer free spinning.

--Driver's side plugged/passenger side normal...4x4 HI on....AC DID revert to defrost after 10 seconds like clockwork. However after 30 secs AC dropped back down to vents like clockwork. Axles at u joint free spinning.

--Both sides hooked up normal....4x4 HI on...AC DID revert to defrost after 10 seconds like clockwork and again after 30 secs AC dropped back down to vents like clockwork...axles free spinning

On the Road test in subdivision...

--4x4 HI...AC reverts to defrost after 10 secs....and then back to vents after 30 secs like above. This cycles seems to follow every time I switch in and out of 4x4 HI. Got out and the axles were locked at the U joint this time....


I'm feel like I am chasing an intermittent electrical short.

Just in my reading, the golf tee test seems to point to my new hub on the passenger side as the culprit. However my axle locking at the Ujoints in my drive tests while the vents are in defrost has me lost. Maybe you fine gentlemen can shed some light on this....

 

Looking like the vacuum pump might not be pulling a hard vacuum. (hard vacuum is just a term I am using). I don't know, but your vacuum pump might be bad. I do know that it don't suck very fast, but it seems to catch up after a while. I guess the next thing to do is to get a vacuum gauge to see what it is.

I don't know if it is an electrical short or not. If it is, it would be in the switch.

EDIT: When I turn my switch to 4x4 it goes in right away. When I turn the key on, the fuel pump and the vacuum pump comes on.

EDIT: Again. If I had your truck in my shop, I could find the problem faster.

 

I understand...I appreciate your input miller....just a little too far to LA for me..


When I turn my key, vacuum pump comes on as well.

When I switch to 4x4 I hear a click....but the axles don't lock immediately.

Tell me more about testing with a vacuum gauge.

 

The axles wont lock immediately if you are sitting still. I sometimes takes movement to lock the hub in, and the light on the dash wont come on until they do lock.

 

nm...........

 

Ok fellas....I have borrowed my buddy's Mityvac....any idea what I am looking for pressure wise besides it actually just being able to hold a seal.

If my pump or solenoid is bad and only works part of the time, I would assume the pressure could be less than required causing my issues.....

 

Just to conclude since a majority of the threads I have been reading do not come back and confirm the problem they had after posting their questions and troubleshooting .

My vacuum problem ended up being the knuckle seal on the hub I replaced just over a year ago..... After changing my shocks and steering stabilizer, I tackled the dreaded knuckle seal. After reading some nightmare type stories of ruining seals with the "homemade tool" made from galvanized pipe, I made sure my flange tool was shaved down so it went down into the seal and rode on the meat of the metal as mentioned here. After greasing the seal, and cleaning up the axle area the seal was to slide onto, it went on like clockwork with just a couple of good solid whacks on the homemade tool with a hammer..

The rest of it went just as smooth. 3 hours total including the shock and steering stabilizer installs. I would caution one to make sure you have the rotor shield on correctly before you tighten all the bolts down......don't ask me how I know......

Took her for a drive with the new "ride" and shifted her into 4x4HI.....She shifted in and out just fine and my AC stayed in the vents......

Knuckle Seal Part Napa Part # 28600 bought locally .....SKS brand $31.50..(Ford wanted $59)

Yellow o-ring $4.75...from Ford house.

Thank you gentlemen for all your help.....no telling how much money this place saved me this weekend......plus it gave me a much needed refresher on the hub bearings in case my other one goes out.

 

just saw this thread, and thats exactly what i was gonna post about the "knuckle" seals i have the same problems! on both sides. for now, i just deal with it and get my *** out of the truck. lol

 

Glad you found your issue, I too have a vacuume leak somewhere in my ESOF system. I think I have narrowed it down to the piping between the switch on the sidewall and the frame sections of the tubes.

 

This might help: