my truck just started making a noise a few days ago and it some what sounds like rubbing a bag of marbles in your hand but only when its in gear. when its in park or neutral i hear nothing. at first i thought maybe steering shaft running on my LTs that i just installed cause it started a week after the install but thats fine with plenty of clearance. i cant check this myself cause the truck needs to be in gear so i can check it out and i have no one around right now to help a guys out. any help would be appreciated guys thanks

 

It's probably just the added valve train noise that comes with LTs.

ETA: Re-read the OP and I don't think this is the problem. Flexplate maybe?

 

so your thinking flexplate, ill have to check that out tomorrow. what about maybe water pump or ac compressor