I have been using this forum since my recent purchase of a 2000 F250 Superduty XLT 4WD. The information you all have been providing is invaluable and i thank you for all the past posts and help you have provided other vehicle owners.

Recently, the front prop shaft broke and upon removing it, I discovered that the vehicle's 4WD was still engaged.

The control switch on the dashboard is on 2WD. I have unlocked the front hubs turning each hub counterclockwise. I have replaced both relays in the engine compartment.

When I rotate the control switch on the dashboard in and out of 4WD, there is an audible clicking in the solenoid mounted under the transfer case, so it's getting power to that point.

I have replaced the prop shaft but concerned about it still engaged causing unnecessary wear. Any help would be greatly appreciated.

 

How do you know that your truck is still in 4H? Are you looking at the light or using another method to make that determination?

 

There is no indication light on, i am only going by the fact that the front prop shaft is still locked and will not turn freely.

 

Put a manual shift transfer case in it.

 

Sounds like something's hung up in the T Case to me. Have you moved it since you replaced the shaft?

 

The auto lock is very finicky.

I just completely rebuilt my entire auto 4wd on my 2002.
Took some time and cash.

there are some main functions.

1) transfer case. if your hearing the clicks, chances are that is ok. but not guaranteed.

2) When you click into 4wd High. There is a solenoid that vacuums approx 10 to 15 (forgot the scale here for vacuum).
first I plugged into the output of the solenoid (passenger fender, white top) to see if it works. itll hold that vacuum for approx 40 seconds then release. This is suppose to set the hub into lockmode.
then I check for release vacuum. its around 5 to 7 on the vacuum meter. this is a must to release.
Also takes about 40 seconds. then the solenoid releases the vacuum.
Know that I knew this worked, I was able to check each wheel.

3) I repeated the test at the chassis where the tube meets. By plugging in on the driver side I was testing the passenger side vacuum
if i had everything at that point I knew I could go further.

I had to replace tubing (as it was missing) and solenoid.

4) next is the hubs and the knuckle seal.
this is usually the problem. I replaced both hubs with fresh one, but you can rebuild them. they have to be properly lubricated at least once a year. and should be put in 4wd once a month.

In the knuckle there is a large seal that hold vacuum in the knuckle chamber. which goes to the hub. for auto engage and disengage.

in the help area there is some info on tear down of a hub, lubrication and rebuild.
you can tell if you have a vacuum meter.
you check at the chassis on the opposite wheel.

I found a smoke injector at this point and pumped some into my hose going to the knuckle.
this would tell me if there are leaks.

I had the passenger side not release, drove me nuts. smoke injector showed me the smoke coming out of front of hub.
So the rubber O ring on the new hub was defective or to small.

hubs were expensive $150 to $200 each.
I bought 3 sets of Chinese versions on amazon (not recommended to buy cheapie stuff, but it was an attack vector I chose) as they were like $35 each I figured out of 3 sets I could get a working set. And I needed to as I had issues with 50% of the cheap ones.
But I was still ahead.

and I had a few to take apart to see how they worked and to test with.
I also pulled apart the wheels and knuckle and put in fresh seals. ( need special $90 tool) to put them in at the right depth.)

I also lubed up the new ones as they were really thin on, or had no grease.
don't flood it as the vacuum needs to get in there. Flooding it with grease will stop you in your tracks.

Morrel of the story is you need that 10 -15 to set the 4wd and 5 to 7 to release.


I also bought a pump by hand vacuum and gauge unit so I can manually test setting and releasing the lock by plugging it directly to the knuckle vacuum pin.

Youll have an easier time with a jack to get the tire off the pavement to see if it locks and releases.


I bassically had to rebuild and replace everything as the previous owner saw no value in the 4WD and when it broke they removed the hoses.
the passenger hub was frozen stiff.

Its alot of maintenance to keep the auto system running.
some just keep good hubs and get out to manually lock them.

Im restoring my truck completely so the time and money was worth it to me.
good luck
Let me know if you have questions
-DRPS

 

Tumbleweed - Yes, I did back up more than 10 feet and came forward the same distance. Repeated it multiple time.

DRPS - That was an extremely informative post which i greatly appreciate and I will definitely follow each check. The previous owner neglected to perform any maintenance on this vehicle so I am slowly reparing and restoring it.

I did notice that the passenger side hub was a little flimsy when I unlocked it. I thought it was going to pop off into my hand. I am also getting vibrations at about 45 - 50mph which i see some refer to as driving over rumble strips.

I think for the time being, I am going to remove the front prop shaft to prevent further wear or damage until I can get this issue resolved. Besides the truck drove more smoothly with it off.

Thank you all for the information and a starting point to fix it. You all are awesome.

 

OP I think you're making this more complicated than necessary.

You need to determine what exactly is not releasing. If the driveshaft doesn't spin freely in 2hi then both hubs are screwed up or the t-case is not shifting into 2hi

 

Yesterday I removed the front prop shaft until I am able to resolve the issue. I didn't want unnecessary wear on it and the truck drives better without it since it was causing vibrations at 40+ mph. I am going to start with the hubs then move to the transfer case.

Any suggestions on a decent vacuum meter?

 

Now that you have the shaft out you can narrow it down. Neither the T Case nor the nor the differential should turn when moving in 2WD. Move the truck slowly while someone watches.

 

Most owners of the first and second generation trucks with failing ESOF hubs will just replace the stock vacuum hubs with a set of Warn or Mile Marker manual hubs.

Yes you'll have to lock the hubs manually when you need 4 wheel drive, but honestly I drove a manual 4x4 system for 12 years here in Northern Wisconsin. It isn't a huge deal. I'd just lock the hubs if there was a chance of needing 4 wheel drive. That meant they were locked pretty much all winter.

 

Don't even need to do that, with the front driveshaft out the the yoke on the front axle and on the front output shaft should turn easily by hand, if one of them doesn't then that is where your problem is.

 

My '11 F350 didn't get vac hubs. Like you I'll likely lock them here in the next couple weeks and unlock in March or April.

You really shouldn't get unusual vibes, even at highway speeds. The astute operator may notice a bit more of a hum from the additional rotating mass, but it's subtle.

 

That's all I noticed with the hubs locked, a little more noise.

My 2019 F-250 has ESOF. I will run that until the hubs or vacuum system fails, then install Warn hubs. I've fragged a few Ford OEM hubs, but never a Warn hub.

 

The elimination of the disastrous vacuum hubs and plugging the system is the most solid advice you'll ever get. I did my first set on a 01, I thought I'm smart, I can rebuild these vacuum hubs, I took them apart, i massaged all the plastic junk inside, I lightly lubed them, they stuck it in my **** in 12" of snow with the plow on. Mile Marker 449SS (autozone, 149, I show 182 and coupons get you below 160 picked up same day), heavy as hell, put em on without a thought, worked good entire winter, next winter they wouldn't lock up, called mile marker and the guy was like "Seriously? On a Dana 60 front? Yeah, no, let me talk you thru taking them apart" I didn't need his help really, but I didn't want to void the lifetime warranty. Upon taking them apart I found the grease had caked and solidified, just like he said. I lubed the internals up with synthetic low temp grease and never had to deal with them again for 9 years. Warns are the same deal, just HUGE hunks of 2 solid metal sliding gears and a wave spring, there is next to nothing, except for poor or under lubing, that can go wrong. Again they're almost so stupid over built they're bullet proof vs the shoddy fragile vacuum hubs. Remember to get 2 1/8NPT plugs, remove the vac hose, then the hose barbs in the spindle (if it snaps off jam a few toothpicks in there and break em off flush then JB Weld the hole over) if the barbs come out put in the pipe plugs to seal up the spindle/hub assembly. Forget which hose up on the pass side at the pump you plug, but it eliminates the 2 hoses down to the spindle.

As far as the xfer case, if you have the front driveshaft out, and the switch is at 2wd, the front output from the xfer should free wheel or at least be moveable (drive forward and back 20 feet each way to make sure the case has tried to disengage internally), if its locked and you can hear the actuator motor trying to do its job, there is some issues inside that are keeping the fork from moving the engagement section and it could of stripped the end of the actuator motor. I mean the motor may sound like its trying to do its job, but its just free wheeling inside the xfer case and not moving the shuttle. Here again, a manual xfer case would be a bonus, and if there is truly an issue inside the power xfer case and not just the shift motor needing a replacement its going to be cheaper to buy a manual case and the shifter lever than for a shop to R&R the xfer case, crack it, rebuild even just the shaft, slap seals to it, and button it back up. A R&R full rebuild with bearings, new chain cogs, chain, seals, fork buttons is 1500+.