jmcn80

I've seen many threads about 04-06 F150s having problems with the vacuum solenoid going bad and causing the truck to slip into 4 wheel drive by itself. I was having the same problem and replaced the solenoid. The problem still exists. The Ford dealership says it could be the shift motor or a part in the front differential that went bad. The truck is lifted so I have a vibration when in 4 wheel drive. This is how I figured out the problem. Any help would be appreciated as the dealership is going to bend me over to find the problem. Anyone have this problem?

ATOM

the easiest way to figure out what is broken is to have the 4x4 vacuum pump checked. i hope you put the new revised IWE solenoid on when you changed it, the one that has the surround on the back side. one of the lines could be ripped, the actuators could be ripped/cracked, the hubs went bad...i just replaced an actuator of the father in laws truck, it had a tiny crack in the rubber seal on the back side. the 4x4 locks itself in because when the 4x4 is off, a vacuum is creathed pulling in the wheel ends, when the vacuum is gone, you are in 4x4. it's a common and easy fix and you rarely can tell by looking around what is the problem, save yourself the BS and just take it in and have it vacuum checked

jmcn80

Thanks for the reply. I forgot to mention that when I'm driving (usually above 40mph) and shift to 4 wheel drive (selector next to steering wheel on this model) and keep some pressure on the accelorator the 4 wheel drive turns off...would that be vacuum?

ATOM

you got a vacuum issue