Ford shift on the fly - no 4HI

UPDATE - it works now.
Vacuum pump was working fine. I jumped the vacuum hoses at the solenoid, put it into 4wd and it worked just fine. I did that a few times and it worked every time. I figured I would buy a new solenoid. I hooked it back up to the original way and tried it out..it works. I dont know if something was stuck somewhere but its all good now. Jumping those vacuum hoses did something to 'un-jam' something. So I am leaving it as it is for now.

This isnt true. I had an 06. I had bad vacuum lines to the front, but it would still go into low. Basically it have me a 2wd low. I used this so the time backing my camper up a hill into my driveway. I never fixed mine on purpose. The vacuum lines up front are a common problem. Next time you put in in 4wd turn the fan up and see if it switched to defrost. This would indicate a vacuum leak.

Did that trick as well right off the bat, it does not go to defreost

austinjenna wrote:

so the steering does bind up in 4LO?

Has it always done this?

Are you sure locking the hubs is not required?

You can place the hubs in 'auto lock' mode. When using the switch on the dash its supposed to be able to switch into 4 hi or low.

Since it does switch into 4 low my assumption is the vacuum lines are fine - there is only one vacuum line that runs from the pump to the hubs. I would think if there was a leak it would not switch into high or low.

What I mean by 'binding up' is that I know its in 4 low because of the low range when i drive and if I turn the wheels while driving on hard pavement the wheels will 'skip' or bind because I am on dry pavement. So I know 4 low is working fine.

if I switch into 4 high the dash light comes on but I never feel it engage. Also if I drive it slowly and turn the wheel there is no binding. I can turn the wheel the entire way and make a circle no problem. If it was in 4 high I would feel it skip and bind

This isnt true. I had an 06. I had bad vacuum lines to the front, but it would still go into low. Basically it have me a 2wd low. I used this so the time backing my camper up a hill into my driveway. I never fixed mine on purpose. The vacuum lines up front are a common problem. Next time you put in in 4wd turn the fan up and see if it switched to defrost. This would indicate a vacuum leak.

So whether the hubs are on auto or manual, no binding while turning in 4 hi, but 4 lo locks up in either auto or manual hub? Then I stand corRected and would say it's probably the servo motor or something with the t case not the hubs.
Good luck getting it repaired

so the steering does bind up in 4LO?

Has it always done this?

Are you sure locking the hubs is not required?

You can place the hubs in 'auto lock' mode. When using the switch on the dash its supposed to be able to switch into 4 hi or low.

Since it does switch into 4 low my assumption is the vacuum lines are fine - there is only one vacuum line that runs from the pump to the hubs. I would think if there was a leak it would not switch into high or low.

What I mean by 'binding up' is that I know its in 4 low because of the low range when i drive and if I turn the wheels while driving on hard pavement the wheels will 'skip' or bind because I am on dry pavement. So I know 4 low is working fine.

if I switch into 4 high the dash light comes on but I never feel it engage. Also if I drive it slowly and turn the wheel there is no binding. I can turn the wheel the entire way and make a circle no problem. If it was in 4 high I would feel it skip and bind

Im so glad I have manual hubs and xfer case

austinjenna wrote:
Its easy to determine if it goes into 4 low. I put in N, flip to 4low, put in D and you can immediately tell because the engine revs up when giving some gas and I am going like 2 MPH.

I can tell its not going into 4Hi using the switch because I can flip the switch drive and turn the wheels and I get no binding at all.

If I manually lock the hubs drive and turn the wheel it will start to bind up so i know its in 4wd

so the steering does bind up in 4LO?

Has it always done this?

Are you sure locking the hubs is not required?

There's a vacuum valve that operates the front hubs, it operates on 12v and switches the vacuum to the front hubs. I would start by checking to see if it's switching the vacuum to the hubs on and off. Vacuum on to disengage the hubs, vacuum releases to engage front hubs. I don't know where it's located on your truck, though. You could trace the lines up from the hubs, or Google probably knows.

A bit confusing explanation, but my armchair diagnosis is the auto hubs not working properly openly.

Like Grit mentioned above, it is possible for the transfer case to shift to 2 low, adding gear reduction, and the hubs still not locked, under the right circumstances. When shifting to 4 low, check for serious bind when turning, to be sure hubs are locking.

They are. It will bind up when trying to turn