I just bought a 2001 Venture Warner Bros Edition and the windshield wipers are very loud when they are on.It sounds like a loud banging noise when they rotate down.
Its more of a banging sound when the wiper blade swings all the way down.It seems the drivers side blade bangs into the passenger side blade.Nothing seems loose

They shouldn't be loud, my 99 is relatively quiet. If you pop the hood and look to the upper left (passenger side by the firewall) you'll see a triangular shaped plastic cover that is just cliped onto the engine compartment edges. It will simply slid off by pulling up on the clips. Under it is the wiper arm mechanisms. Turn on the wipers and look for any excess movement or loud sounds, you should see the problem there. Look for loose arm connections, they are held together with very small screws, you may have one or two missing.

I had a 97 Voyager and now a 02 Venture and these wipers are very loud to my compared to my 94 Tercel and 92 Supra.

What I did on the Venture was greased the mechanism very well but that didn't help much.

Yours is probably worn and mine probably is too.

Darren.

Also, check the motor housing mounts, make sure they are tight. If loose it can give you your "knocking" sound as it shifts from side to side during rotation.

Its more of a banging sound when the wiper blade swings all the way down.It seems the drivers side blade bangs into the passenger side blade.Nothing seems loose