The F250 did what your truck is doing a few years ago. Grinding and not engaging. Called a large Ford dealership and was told it was a leak in the vacume lines near the wheels, $425 to fix $25 in parts, 4 hours. Never tried four low after that, then one day my ac/heat controls started to act funny. The vacume leak was causing the cabin controls to only work on the defrost position.
My mechanic tried a new pump with no luck but managed to bypass the vacume lines going to the front and now the cabin controls work normal.
Recall people on forums using a aftermarket stainless steel covered vacume line for the front end leak problem.
My mechanic tried a new pump with no luck but managed to bypass the vacume lines going to the front and now the cabin controls work normal.
Recall people on forums using a aftermarket stainless steel covered vacume line for the front end leak problem.
