Bought a used 99 f250 super duty. Truck hops in the front end on slow speed turns as if 4 wheel was engaged...sounds like the issue? I went under the truck tried to manually spin the hubs and drive shaft to transfer case and all are locked in place so seems to me its stuck in 4H...wouldnt that be a sign its stuck in 4H/4L? I know on my dodge trucks my transfercase shaft spins freely not engaged..come to find out the switch inside cab doesnt work windows n locks didnt work (fixed that mess already) but did some research on the 4 wheel set up and understand the vacuum lines.. Well the nipples on the hubs are rotted off and i dont see any lines that would even run to them. I did trace them coming from pcv or what ever valve it is near holding tank and noticed where ther lines should go to the hubs are connected with clear tubing together.. So tomorrow im going to get new nipples and new vacuum lines but my question is....i cannot manually turn the hubs the black cap that has like the lever on it came right off and white part inside came out along with dirt ect. Do i need new hubs or if i fix the vacuum lines and figure out why the switch wont work or light up 4x4 on the dash(yea that's another problem feel free to input there) do u think the hubs will engage and disengage? Any help with this system is appreciated

 

The front hubs are locked up. Take them off, inspect them, clean and lube them or repair/replace as needed.

 

If you had one of the auto hubs fall apart in your hand, you need new ones. You can replace with manual hubs (which i recommend). Depending on how long the 4x4 switch has not worked, you may be able to get it to work one more time... have some one in the cab turn the switch to 4x4, then back to 2wd while your knocking on the transfer case shift motor with a hammer. It may just move one more time..

More than likely though, you need to replace the shift motor. I wouldn't worry about the vacuum lines that did or didn't used to be there. Go with Manual hubs, and change the shift motor. That should get you out of 4wd, and back to 2wd..

 

If one came apart in your hands you will need at least one new one. If it was that bad the other can't be far off. Could be that the hubs were never unlocked or that the locking hubs are frozen. Looks like it has been patched at least once. There's so many places to start and where to check so I'd recommend a search so that you can start to check the system out. If you have vacuum lines you have the ESOF system (Electronic Shift On the Fly). You should check to make sure that the electronic portion works as well.


I've not had an issue with the electronic side (switch operation and transfer case engagement) so I don't have a lot of intimate knowledge of that but I have been through a few mechanical problems with the vacuum hubs. I would start with cleaning the locking hub that left if you want to try and keep that one (they are not cheap). Here's a write-up:


Welcome to guzzle's 4x4 Autolock Hub Lubrication Maintenance Web Page


Here's some threads I've been involved with over the years. I didn't proof them but there should be some good info in there somewhere if you want to check them out:


https://www.ford-trucks.com/forums/8...-engaging.html
https://www.ford-trucks.com/forums/1...ront-hubs.html
https://www.ford-trucks.com/forums/1...s-failure.html
https://www.ford-trucks.com/forums/8...rake-line.html
https://www.ford-trucks.com/forums/8...-troubles.html
https://www.ford-trucks.com/forums/9...-question.html
https://www.ford-trucks.com/forums/917073-4x4-hubs.html


I hope this helps. Good luck!

 

Removed motor from transfer case took 5-8" wrench manually turned gear end after a bit of force and turning drive shaft a little at same time it went thru both 4h/l n 2wd. Eventually got hubs to unlock and lock after taking caps off and cleaning crap out of it. They turn easy now. Left transfercase.motor off for now till i rewire everything not expecting rain anytime soon and dont.plan on mudding this is stricklt work truck so no big rush for four wheel drive. Just glad the hop is gone.. Knew it was related to 4wd

 

Good that you were able to get it sorted.

 

I was working on a friends truck tonight that is also stuck in 4 wheel drive. There is no signal coming to the relays that control the transfer case shift motor. We can pull the relays and manually jump the connections to make shift motor run but nothing whith the switch. Any suggestions?

 

Ya, get a new relay first. cheap.. unless you jumped the proper wires on the relay, and heard it click and make the motor run. I would suspect just the relay.

After that, get a new switch. I have heard of problems with them, but not that many. Last part is you may have a weak shift motor, or a bad position sensor on the transfer case.

 

We had one new relay and there are several relays on the truck that are the same so we have been switching them around. We never get a click out of any of them when they are plugged into the shift motor but they work in the other positions. It sounds like the dash switch is next.

 

hey bud check all the wires and connections for the green corrosion build up. That ****s a bitch and causes all kinds of problems. Thats y i wasnt getting any clicking. Cleaned everything up nice put old solenoids back in i got clicking but nothing else. Ended up being everything failed at once. Hubs were full of dried up mud/clay motor on transfer case burnt out to to trying to shift and switch for on the fly burnt up. Can now manually turn hubs with a bit of force and left transfer case motor off and welded up a incased lever to manually turn transfercase over to four wheel... screw this electrical bs...if u wanna see pics ill post here...took some time but ran linkage to the cab and now have handle near driver seat to manually do everything works so much btr and can guarantee no more issues with four wheel failing..by the way works real well in mud holes shifting love it