I have a 1996 Chevy Express 1500 van. RWD with 5.0. During light braking or deceleration (probably around 30 - 35 mph), it makes what I would call a rhythmic thumping or chopping sound. Though it is hard to describe a sound in words, the best way I can describe it is that it sounds like fan blades striking something. I realize there is a cooling/radiator fan on the vehicle, but I would presume this van would must likely be on only at idle.
A shop mentioned that this thumping was coming from the crossmember (which I actually did not even think my van had) and that someone had forgot to replace a bolt when installing my catalytic converter. I am not sure what to make of this, or how I would be able to verify it for myself. It seems like “crossmember” can mean different things to different people.
Any advice would be appreciated