Bad noise
This is my first post, so welcome everyone and thanks for all of your help.
I have a f150 1999 xlt 4*4 and I have a major noise coming out of the front differential when i put in 4*4 it sounds like a major slip in the "gires". Both drive axel are new. Is there some kind of pin that does not go in all the way and activated by a vacum malfunctionning.
I'm open to all suggestion.
Thanks for your help.


