I was driving down the road doing around 30-35 and I heard a grinding noise that happened really quick. I pulled off onto a side road and looked around, saw nothing wrong. So i drove home and looked again and still saw nothing wrong

Then I did some research and found it could be my 4WD vacuum actuator?

I know the iwe actuators for my 4wd were replaced a month or two ago because of a grinding noise

Any ideas?

2005 f150 4.6

 

I was having the same problem i replaced my IWE today hopefully that will fix it ill find out in the morning i guess mine goes into 4 hi hard now i get a grinding noise then a clunk or bang and then the 4 hi engages its not all the time though usually the fist time going into 4 wheel drive

 

Oh and I forgot to mention that after I got home I took it for a test drive and put it in 4hi and drove down the road at like 30 mph and i could hear a faint sound. Couldn't make out what kind of sound it was either. But when i put it back in 2wd it went away. Not sure if that has anything to do with it or not but I figured I'd mention it

 

Read through this to get spooled up on your 4x4 vacuum system. It's fairly simple and easy to diagnose/repair. Parts are generally cheaper online, but my dealer will match some online prices.

http://www.ford-trucks.com/forums/836438-everything-you-wanted-to-know-about-the-iwe-system-and-then-some.html

Let us know what you discover...

 

I had this same problem with mine changed the differential oil and it never did it again try that it might work