I bought a 99 V8 Laramie SLT Dodge Ram about 6 months ago. Even though I like the truck a lot, I've had my share of problems. I've had the rear brake drums, lower ball joints, plenum gasket, serpentine belt, rear tires, and water pump replaced. Now she runs great. However, whenever I get it back from the shop I hear a noise similar to hearing upstairs plumbing while in the basement. It sounds like water is flowing around under the dash. It only happens when I accelerate or brake, but it doesn't seem to be related to the engine spinning. After a few weeks it went away last time, but now it's really annoying. Any ideas?

 

Check the coolant level, you have air in the system. The noise you here is coming from the heater core, which is under the dash.

 

https://dodgeforum.com/forum/2nd-gen-ram-tech/181153-gurgling-noise-in-passenger-side.html

here you go.