I wasn't sure where to post my question but I am going to try here first.

My truck is a 1998 F-150 4.6 manuel tranny with 4x4 shifter on the floor. Sometimes when I try to shift in to four wheel drive it works great, but other times nothing happens. No light, does not lock in, nothing at all. When it decides not to work I can shift it back and forth and may never work or after 20 times it might. Can anyone explain this or have any ideas as to why? When it doesn't work I have checked the vacuum lines and I have it in both lines........ Please any ideas are welcomed

 

The fact that you're not getting the light troubles me. The light is connected to the transfer case. So even if the vacuum disconnect wasn't working, you should get a light. Actually, the light is connected to the shifter.....you should even get the light if something was busted in the transfer case. When it won't engage in 4hi, what happens if you try to shift it into 4low?

 

Does it actually engage 4x4? Again try 4Lo to see if the t-case is shifting. The switch on the t-case is what tells the GEM that you have shifted into 4x4. If the switch is defective the GEM will not engage the front axle. A quick way to test the t-case for positive engagement is to jack the front wheels off the ground. With the tranny in gear for a manual tranny or park for an auto then with the key on shift into 4x4. Either Hi or Lo it doesn't matter. Once you have shifted get under the truck and try to turn the front drive shaft. It should not turn. If it doesn't then I would suspect the switch.

Regards

Jean Marc Chartier

 

He has a manual x-fer case like mine, no switch.

I'd check the linkage, may need some adjustment. Good luck

 

There is a switch on the Manual t-case. PN E7TZ 7E440 AA. It is #12 in the picture.



Regards

Jean Marc Chartier

EDIT: The revised part number for the switch is: 4L3Z 7E440 AB

 

ah I thought you meant the 4x4 switch on the dash for those who have electric t-cases.