Last Sunday I went to this mud bog in Central Florida. (www.mudup.com)

Well, my four wheel drive was working, which is always nice. I was able to get all four wheels spinning. But, even though my dash said that it was in low-range, it wasn't. My truck was only locking into 4-hi. Can someone point me in the right direction to diagnosing the problem? My truck used to lock into low, but I am positive that is wasn't on Sunday. I am also positive that it WAS in 4-hi.

Help?

Thanks.

BTW - I finally got a few pictures posted.

 

I don't have the book with me (that little one in the glovebox that comes with the truck when you buy), theres a procdure to follow to get it to lock into low. I never attempted myself , but it's in that book..

 

Oh sweet. Thanks man. I thought there might have been something related to vacuum lines or something.

 

Just checked and I don't have that book. Maybe someone will view this post that has that book and can maybe check for me.

 

To shift to 4lo, you must be stopped, trannie in neutral, foot on the brake. Then you can shift.
You can download a pdf version of the owners manual at www.motorcraftservice.com in the owners section.

 

I know that you must be stopped, blah blah.... When I switch it to 4-lo, the dash lights up with Low Range, the 4wd locks in.... it just doesn't lock into low. It stays in 4 high. I know how to lock it into 4wd. As I said, it used to work. It just stopped going into low range all of a sudden.

 

If it used to work (i.e., you are following the proper sequence for getting into 4-Low) then you might have a bad solenoid on the transfer case. I don't know that much about them, but I know when I drop either one of my 4X's into 4-Low I hear the solenoid kick in.

 

Do your brake lights work? If the switch is bad it will not know you have your foot on the brake.

 

If the 4low light is coming on in the instrument cluster, that means that the transfer case shift motor is seeing the shift fork roll around into the low range position. If the shift rail turns to the 4low position, but the low range gearset does not engage (but the lockup collar still does) you've got some serious voodoo going on in your transfer case. It should not be physically possible for the shift rail to move the lockup collar and not move the low range gearset in and out of mesh. How it's happening is beyond me, but it'll warrant a tear-down to see what's broke.

The first place to start, however, would be to verify that's what's happening. Shift to low range, then pull the motor off and see where the shift rail is pointing. If the shift rail is pointing to 4low, but the low range gearset isn't engaged, then there's your problem.

-Joe