I have a problem. while driving in 4x4 my truck seems to pop out of 4x4 with a violent clunk that shakes the truck. Then pops back into 4x4 after a second or two. It does this repeatedly. I don't have any grinding sounds. the truck seems to shift from 2wd - 4hi-4lo without any problems.
I have read many other posts trying to find something similar but can't.
what should i look at first? TC, Front diff, hubs/IWE?
I am able to do the work but not sure where to start.

 

Somewhere around here is a thread dedicated to troubleshooting the 4x4 system on these trucks, and I can't find it right now, otherwise I'd post a link for you.

If it's slamming out, it sounds like the transfer case more than the IWE/solenoid issues, JMO.

 

Sounds like your HUBS are shot...if it will engage/dis-engage the IWE's are working corectly..when you selsect 4WD it vents the vacuum from the IWE and engage's the IWE with the HUB...if its not staying engaged the gears where the IWE and hub mesh are worn... I would look there first...good luck

 

Thanks, I'll be putting the truck in the garage today to start trouble shooting.

 

Good Luck

 

https://www.f150forum.com/f72/how-di...m-esof-186872/

 

Thanks that was the linky I was looking for.

 

So I've been too busy to get a good look at the truck. But I've found that it does not pop out of 4lo. It's only happening in 4hi.

 

I have found that the problem is only happening in 4Hi. Not a problem in 4Lo.

 

I had this issue and it ended up being the little IWE solenoid in the engine bay (passenger side).
Found out after spending unnecessarily on other parts.