Hi I have a 2006 ford f 150 that makes a noise almost like somethings loose underneath in 2wd. When put in 4wd it goes away. I have gotten a good bit of info from here but I have had my truck to the dealer and they said that there was a blockage in one of the vacuum lines and it wasn't covered under warranty so I had to pay $150 for them to look at it and it would cost me $95 for the vacuum lines. Then I took the truck to another garage whom I know quite well and he said that it was the shift motor in the transfer case from not using the 4wd switch enough. He said there was one vacuum line and he said it was free of any blockages. I want to call the dealer and give them hell for charging me $150 for nothing but I don't want to do that incase my guy maybe wrong. Could I get some feedback on what is most likely the problem before I go any further?

 

My 04 made a similar noise but it was the vacuum solenoid that was not engaging disengaging properly. This was a known problem with the 04's which my dealership replace free of charge. Not sure what could be in the lines to create a blockage.

 

so you have noise in 2wd, but no in 4x4, correct? classic sign of your IWE solenoid shorting out. being you have a 06, depending on build date, you probably have the old designed IWE Solenoid. takes 10 minutes to swap out. here's a how to http://www.f150online.com/forums/art...-pictures.html

1 vacuum line? there are 2, 1 going to each front hub actuator.