I just installed the valve yesterday. My truck is an 03 CC 4X4 7.3 auto with a SCMT and drop in K&N. It has 53,000 miles. Since installing the tuner, the 1st to second shift hesitated under full throttle. The valve is 7/16. Factory is 3/8. I assume it is similar to the Sonnax. I only changed the valve with stock springs. The shifts really quickened up, but they are not neck snapping. The change was very easy as the worst part is the mess of dropping the pan. The fluid was very clean with little normal greasy sludge on the magnet. I am very happy with the results. The valve was given to me from a buddy that is a Diablo dealer as he owed me a favor.