Got stuck on a muddy road so I tried to put the truck into 4wd-Lo (from park and neutral) and the front hubs never locked.

I did hear a clunking sound like the hubs trying to lock and the indicator showed locked but the front wheels never grabbed.

Was able to get my way out in 2wd after 40 minutes but definietly have a problem with my 4wd.

I have noticed that in 2wd the front wheels seem to grab during sharp turns in the parking lot like the hubs are not fully disengaged. I have driven in reverse 30-50 feet and tried everything I know to do.

Any suggestions on troubleshooting or fixing the problem?

2003 F150 Supercrew FX4 Lariat with stock 4x4.

Ed in Oklahoma City

 

First, you do not have hubs. 97-03 are center disconnect. They lock or unlock the front axle at the diff. The front half shafts always turn. Just a CV joint at the wheel.
If the front axle is not locking, and the transfer case is working, the problem will probably be with the solenoids that send vacuum to the vacuum motor on the diff, a broken or leaking vacuum lines to the vacuum motor, a bad vacuum motor, or a sticking or broken shift fork in the diff that axle does the engage/disengage.
Best way to make sure you are going into 4x4 at the TC is put it in 4lo and see how high the rpms go at low speeds. 4lo works the engine quite a bit more than 4hi/2wd.

Edit - Should ask, do you have the manual lever or the ESOF? If ESOF and the transfer case is shifting, then it is unlikely any problem with the switch. If manual, it could b the position switch is bad so it doesn't know it has been shifted. My bet is on something on the activation of the center disconnect.

 

Thanks for your help.

First, I'll check the motor on the back of the transfer case to see if it is working (telling the transfer case to engage).

Second, I'll check the vacuum line on the actuator on the passenger side to see if it is working.

Third, if both the motor and actuator are functioning then it is either the fork or the transfer case.

 

Or it could be the solenoid on the firewall. There are 2. One engages and one disengages. Both are on the firewall, passenger side near the hinge.

 

Don't overlook just a sticky engaugement rod on the front diff, its easy to lub, just pull the plastic cover off, (3 screws) find the shift rod peel to boot back, and try pushing in and out with your hand, give it a shot or two of PB blaster and work it by hand a few times.
This is common especially if you don't use it much. This happens from time to time of 97 with manual 4X4 shift. this is easy fast, and a good place to start.

 

Thanks everyone for your help.

Found out the problem was with the fork in the passenger side of the transfer case.

I'm also changing out the clutches on the rear wheels that were grabbing when turning tight turns at parking lot speeds.

It's a little expensive to do everything at once but at 108,000 miles I should expect some maintenanc.

 

The same thing happened to me about a few weeks ago. It felt normal and it shifted in and out of 4/Low, but the front tires never engaged. It's a manual shifter 97'. How could I check if the front transfer case is engaging?

 

Here's how you 4wd works. You can check all of this while it's up in the air, or just jackstands.

You turn the **** on the dash and it tells a motor down on the back of your transfer case to engage.

If your front driveshaft isn't turning, check the motor.

If it is move to the front axle.

On the passenger side of the front diff there's a lever connected to some vacuum lines that go to an actuator on the firewall next to the battery. If that lever doesn't move, check the lines for leaks or clogs, and then the actuators.

If the lever does move, I'm sorry, but the problem is a stupid little fork inside the axle that's broken.

 

You have one transfer case. The front is a differential, not a transfer case. Same as on the rear, it just engages and disengages instead of always being active.
As stated above, you can check what is turning by putting the truck on a lift and see what is turning. In your case, there is no motor so if the front driveshaft isn't turning, you have a problem with the transfer case or the linkage on the shifter.

 

Hellow,

Sorry for my English because I a French Canadien,

I read your topic end archive because I a same problem with my F150 1997 but I am not sure to understand.When I turn the 4wd selector on the dashbor there is no light on the panel and no click on the relay. My question is who control the light end the relay??????? the selector, trenfer case or differential because i I want gone step by step.

Step 1-???????
Step 2-???????
Next

Thank you.