While traveling to Fla in my '04 FX4 doing about 80 mph, I attempted to turn the A/C fan from low to the second speed and was distracted by my kids in the back seat. I accidently turned the wrong **** and put the truck in 4X4 hi. It actually engaged. I felt a small jerk and the 4x4 hi light came on. I realized what I had done and put it back to 2wd and it made the trip fine. Is it possible that this caused damage????

 

Your fine. Everything was turning at the same speed so it wasnt a big deal. If you would have driven on it for a long period of time that would have been another matter

 

I thought it wouldn't activate at any speed higher than 60? I'm surprised you felt it kick in.

I've done that a couple times, I'd look down and wonder why 4HI was on. Coincidently, my a/c fan isn't running any faster when I flipped that switch 5 minutes ago either.

 

I used to do that a lot in my '99, but I don't think I've done it once in my '05 yet (until tomorrow I'm sure ). I think the placement is a little better in the '05 compared to the '99.

 

I did it in my '07 and it didn't engage. I was going about 65-70 when I did it. I then got off the highway and drove through some backroads to get to work. Only then did I notice the stupid switch was in 4-lo. So, I guess that even if you slow down afterwards, it doesn't engage. Just another reason why I hate dash mounted 4X4 switches. I was a bit upset when I realized you can't get a S'crew with the floor lever.

 

I believe you have to be in neutral for 4Lo to engage, I was always told that running 4WD, higher then 50 was a big no no.

 

Going straight in 4hi is ok for some distances, just don't do a lot of turning on dry surfaces.

 

Engaging it higher than 50mph is a problem because it can't spin-up" the front shaft higher than that speed. I have my 4HI all the way up to 100mph on a desert road with no problems.

 

Get a Lariat 4x4, that will solve all your problems

 

I meant on paved surfaces

 

Well I drove it again today and it seems fine. I may get the transmission and transfer case serviced just to be safe and see what happens.

 

If it makes you sleep better than so be it. It is totally unnecessary, it is a PCM controlled vehicle, if i didnt want to be in 4wd it wouldnt have engaged. And obviously all the 'conditions' were met and it engaged. The transfer case is ALWAYS in 4wd anyway.

 

100mph on a paved surface wouldn't matter either as long as you were in a straight line. Handling/Stability is compromised with 4wd at high speed.

Did you mean anything else? I just want to be on the same page here.