Tommy J

2004 FX4 111,000 miles. Today and on 2 other occasions over the past several months when I park my truck and later come out to drive elsewhere it is in 4 wheel high. I don't realize it at first because its the last thing I am thinking. I initially think the parking break is on and then sort of panic thinking my tranny is shot. Of course I pull aside and then realize I'm in 4x4 high. It goes back in 2 high when I turn the dial and then drives fine. Today it was idling for a few minutes before I got in to drive. The selonoid on the firewall is relatively new with the newer version with a cover. It never grinds or does it when I'm driving with no other symptoms. Whats causing this and what do I look for. Is it a vac leak or something else. Obviously somethings not right and I am assuming it switches to 4x4 by itself after I start up the truck but I don't realize it at first. It has only done this like 3 times in months. Thanks for any input. I just don't know where to begin my diagnosis

screamineagle

Is the dial turned to 4hi when this occurs? If so, try locking your doors when it's parked...

Tommy J

Doors are always locked and yes the switch is on 4 hi when this occurs. I think I have some kind of vac leak or lack of because the lack of vacuum puts the truck in 4 wheel drive I think

PerryB

If the switch is in the 4H position, its either getting put there by human effort or the truck is demonically possessed. There's no way it can turn its own ****.

Lack of vacuum puts the hubs in, but not the T-case.

screamineagle

X2^^^. Either someone or "something" is playing tricks on ya.

Tommy J

Then its possessed! That's why I'm posting this issue. No one is messing with me. It happened at a golf course, home depot and my driveway. I always lock my doors. That's why I'm concerned that the button is actually in the 4 hi position. I don't accidently put it there either in case someone is wondering. I started it yesterday at the golf course and let it idle for a few min as I talked with my friends and got in and experienced the issue so logic would tell me that somehow while it was idling it switched to 4 hi both in button and function.thanks anyway

Tommy J

I highly doubt someone is breaking into my locked truck and turning on my 4x4. I would think they would steal something ...........oh ....I don't know, maybe one of my multiple guns. But then again if its a what and not a who. I won't even get into my remote start "ghost" starting on occassion

nasars

Ive recently had a similar problem that I was going to post. I got in my truck the other day started it up heard a big thunk, pulled out of my parking spot and to my surprise it was in 4 low, the dash switch was in 2wd but the dash light was lit up for 4low. The really weird part is when i turned the switch to 4 low the light went off but truck stayed in 4 low. I had to put truck in neutral turned switch to 4low then to 2wd and it finally switched to 2wd.

Tommy J

I didn't and don't hear anything when it happens not that it doesn't make any sounds though. I'm just not aware of it when it happens. Mine goes into 4 hi and the button is on 4 hi. You may have something different going on that you can probably diagnose. There is a really good right up on the forum about the whole system but I can't find it and my problem is unique

Turdferguson391

Im pretty sure with our trucks when turned off it automatically goes into 4wd from lack of vacuum. So on start up it should create the vacuum causing to go back into 2wd. So maybe a leak on start up