Buzzing noise from floor

I did my intake manifold gasket this weekend and all went well. However, after I finished I could hear a buzzing or clicking noise while the engine is running. It sounds like it is coming from the drivers side transmission tunnel right where the 4WD shifter is. It does get faster when I accelerate and what is weird is it disappears when I let off of the gas and coast when I am doing above lets say 25 or 30 mph. It does it no matter what gear I am in or what gear the transfer case is in. The transmission fluid is fine. I didn't touch anything down there when working on the truck. Any help would be appreciated!

hard ot say without hearing it personally

going to be blindly and wildly guessing from here on the internet

check u joints

check for something rubbing on the driveshaft or other rotating part

good luck!

I got under the truck today. It makes the noise at idle and it doesn't matter if it is in gear or not. You can hardly hear it from under the truck but it is loud from the inside. It almost sounds like it is inside the transmission. It seems to change speed with the change in gears and rpm.

Are you sure its coming from the inside of the transmission? it is hard to say without hearing it. Make sure your dust cover on the front is secure. Is it possible it could be an ABS motor buzzing and going out??