Okay I'm starting to get a little annoyed with my truck now. Two problems I had came back today. When I am driving along, I can hear a knocking noise from the inside of the cab. It appears to be coming from the passenger side of the windshield, or something around there.

AND

The rattling has come back. I was told it was the cat and had it replaced and didn't hear it after. Now, all of a sudden when my truck shifted into OD, I heard the rattling again and its been rattling every time it shifts into OD. It used to also rattle when I would slowly climb a hill, from a stop, SLOWLY accelerate up the hill and I would hear it. But now I tried that and didn't hear it, I could only hear it when it shifts to OD.

Does anyone have any idea on either of these two problems? I'm going to check the bolts for the cat to see if they are tight, I have no idea what else to do. We all thought that rattling noise was my cat all along and now that I got the new cat it seems it might not be that (unless this one is shot, bought it from summit, magnaflow high flow cat).

 

Could be your cat heat shield.

 

i have some sort of heat shied rattle, but its not really that loud, if im going like slow w/ the window open and accelerate @1700 rpm or so its like a heatsheild going nuts and its really annoying ive poked around but nothing is loose from what i can see...

 

yea theres nothing loose on mine from what I can feel. I've gone around most of the underside feeling around and I can't find anything loose.

 

This is gonna sound stupid but it the truck good and warmed up when you hear the rattle, because that thin heat shield material could be expanding and causing that rattle. I'm by no means an expert but it might be possible.......