power steering problem 2001 pete 379

i have a 2001 pete 379, i recently changed out the power steering pump and also steer gear and have hard steering. seams like a lot of steering wheel kick. the list of things ive done with in the last six months...new king pins with load bearings, new steer leaf spring bushings with pins, 3 axel alignment,

if im on a nice highway it drives fine but the moment i get on a rougher road it has a lot of steering kick, almost a real hard time keeping it stright. any help would be appreciated, thanks

 

thanks for the reply. yes when you hit a bump or any uneven surface its hitting and puling the wheel. sorry but i dont know what t steer assist cylinder is. all i know i have a
is the steer box and power steering pump.. thanks

 

thanks for the reply, ive checked the steering shaft and the u-joins and they all seam fine and greased.

 

mine does not have that on the truck. should it have one? thanks

 

agreed! i dont know what else it could be but a friend told me to put 15w40 in it and it worked good for a few days then went back to hard steering wheel and bump steer ect ect. only other thing i can thinbk of is try using atf and changing the filter out again and see what happends, thanks