I just did mine on my 2000 V8 last weekend, I actually did it twice in a row but thats another story. I cannot think of anything that you could have damaged that only makes noise while the truck is in motion. Can you listen around a little more? Can you hear anything parked at idle or in gear at idle? Maybe narrow it down to a serpentine componet? Did you change any other parts besides the WP and TB? oh, maybe check your trans fluid level? Thats about all i got....