Your steering fluid reservoir may need to be replaced. Mine started leaking after upgrading to the 105 box and refreshing hoses. It's an easy swap but your system looks to need a flush at the least. Good luck. Hope you get it sorted soon.
Hi - My truck had a similar issue with wandering, especially at highway speeds. I upgraded the steering components including the box with a 105 series sector shaft and replaced the tie rods. The problem remained until the truck's front axle service was performed. The problem was that the...