Original radiator started leaking. Installed a new aluminum radiator (Griffin). Almost exactly 30 days later it started leaking on the left side in the "fins" portion but near the tank on the left. Got a replacement and installed it (Griffin). This 2nd radiator also lasted about a month and started leaking, this time on the right side, again in the fin area near the tank. Switched manufactures for the 3rd radiator (Howe). Unbelievably it lasted about 30 days and this one is leaking on the left, again in the same area. I assumed I had done something wrong. Took it to a professional who says everything is right, it has to be another bad radiator. These are expensive aluminum radiators from reputable companies (Griffin, and Howe). I'm getting ready to get the 4th and the company where I'm buying them is likely to question so many failures (as I do). The radiator does not get hot and the engine does not get hot. There is no indication of high pressure.
Have your truck looked at for a bent frame or the header being bent. You'll have to take to a front end or body shop that does frame repair for this. Also when you install rad check to see if body mounts are in place in front, they may not be and causing the rads to crack