No 4x4

[MCox32]

I have an 05 f350. The light on the dash comes on but it isnt in four wheel drive, any ideas? I havent checked anything yet but and going to start tom. What should I check first? Thanks for any help.

[durawut]

try locking the hubs in manually

[imstokin]

exactly what durawat said,you have to have your hubs locked for it to work.

[bigcountrysg]

Originally Posted by imstokin

exactly what durawat said,you have to have your hubs locked for it to work.

The hubs should lock in automatically. Unless there is a problem with the vacuum system. When you put the truck into 4wd does the air vents default to defrost. If they do that is a sign you have a vaccuum leak. If not then you have an electrical problem at the t-case. It could be a bad connection with the t-case motor, or the sensor on the t-case. Or the t-case motor is bad and needs replacing. Or the sensor on the T-case to identify if it is in 4hi, 4lo, or 2wd is bad. Which would not allow the t-case to shift into 4hi.

Using a good code reader like Auto Enginuity. You can pull codes like T-case will not shift from 2hi to 4hi, or T-case will not shift from 4hi to 4lo. With these trouble codes you will be able to figure out what the problem is.

[MCox32]

ok ill try the vent thing then if that isnt the prob ill c if i can get a code reader. thanks for the help

[twoicebergs]

The problem is a bit more complex. If the light comes on the truck has sensed that the hubs have locked and that the 4x4 shift motor has engaged into 4Hi. If your hubs do not engage, you will not meet on of the requirements for the differential to engage in 4Hi and therfore no light.

Same goes for 4Lo except it must detect the vehicle less than 5km/h (stopped may be required), nuetral and brake ON.

It is possible that only one hub engaged and that as a result you get nothing based on the design of the front differential power transfer when power is applied due to no limited slip or true lock on the front axle unless you have modified your truck.

[hick88]

the same thing happend to mine the other day, and the air started to blow out the defrost. i thought it might of been a vacum leak but wasn't sure. i looked at what vacum lines i could see and they looked good. any suggestions?

[BAT]

If the light is on that does not mean it is in 4wd, it needs to roll for it to engage if the hubs are not locked.. If I am on trail where I am not sure if I will need 4wd, I lock the hubs. If need to go into 4wd I just turn on the switch and off I go. Once in our jeeps we ran across a guy stuck in his 4wd Super Duty for a couple of hours. We asked if he had it in 4wd drive and he said yes but watching him try and get out the front wheels were not moving. The front wheels could not engage so we rolled up our sleeves and walked over and locked the hubs and the truck just popped right out.

[twoicebergs]

If you are stopped and all the conditions are met, BAT is correct, the hubs could still require movement to engage. If you have ever got stuck before locking the hubs, the worst feeling is not being able to engage 4x4 when you need it the most. There is no guarantee that the 4x4 will engage just by manually locking the hubs.

[ryandamo]

these hubs are a pita, i got a gasser super dudty at work i plow with and i constattly have problems with them,