4wd Accuator System Problems
2005 Ford F150 FX4 8Cyl
Some time ago had an issue with a metal on metal grinding sound coming from front axle area.
The noise seemed to happen mostly when going uphill when the truck was under a load. It would stop as soon as I let off the accelerator. After some trouble shooting found the problem definitely to be something with the 4wd accuators losing a vacuum and the 4wd attempting to engage..... apparently a common issue. I also did some troubleshooting by driving up a hill where the sound would always happen but in 4wd and the sound did not happen at all.
The first step i took was to replace the accuators themselves but it did not fix the problem (figures I took the most expensive route first) Next I replaced the solenoid for the system along with the vacuum hose assembly going to both hubs. After doing that the noise stopped and truck has been quiet for over a month.
Yesterday I towed my boat for the first time since making repairs and the noise returned. It only happened when I was driving on the highway and kept happening when ever going up a steep incline. After i unhooked the boat I drove the truck quite a bit including going up more hills and the noise did not happen at all.
As far as I know I have replaced all parts of the 4wd accuator system and it did seem to work because no more noise but it is still happening when under a heavy load (towing boat).
Anyone have any options I can try now ?