I’ve tried to adjust the preload on the input shaft of the box, but the adjustment point was totally seized up. Couldn’t get it to move with a pin spanner wrench.Assuming you have not tried to adjust the input shaft yourself, you should isolate the gear box. This will validate your claim with napa. It doesn’t matter how new everything else is. The people on the forum have gone down this road before and you are the benefactor of their failures and triumphs saving you time and money. So follow the yellow brick road and you will learn quite a bit. The GMT400 Forum is much like the land of Oz with many wizards trying to get the trucks back home..not saying i’m one of them.
I don’t have the NAPA box anymore, I returned it and bought a used OEM one from marketplace.
Can also confirm it’s the steering box because there’s double the play in the used OEM box as in the NAPA reman box lol.
All the front end has already been replaced and was checked only a couple weeks ago. The ball joints and hub bearings were the only thing that had play in them, and it’s in the air right now, while I’m replacing those. Figured I’d address the steering box while doing those, and it’s turning into a nightmare trying to find one lol.