yea im taking my car to the shop. just wanted to know what u guys think it is, so i dont get scammed or anything....

I had the car in the shop about a month ago to replace engine and tranny mounts and fix a cracked flex plate, it used to make a similar rattleing noise, but it used to make it only before shifts and when i was lightly accelerating as well as when i was revving it up in neutral. the car ran beautiful after it was fixed until now... Some times when i am accelerating, right before it shifts i hear a rattleing/vibrating noise, similar to what happened before it was fixed, but its not as loud and doesnt happen as often. When it makes that noise my gas pedal vibrates. Also when i am idle, im hearing clunking and ratteling coming from the passanger side of the engine compartment. And my car is a 4L60E, i got a shift kit, it shifts hard into 2nd, and everytime it shifts hard i hear a loud bang from that same area, sounds liek something hits something. As far as the acceleration and performance, it doesnt seem to have been affected alot. What do u guys think it might be?

Oh and i parked the car, popped the hood, and tried to see if maybe i can see a problem, but i coudlnt see anything, infact i didnt hear the noises as much when i was looking under the hood, compared to when im inside the car with all windows closed, maybe its my exhaust tone... but yea nothing seems wrong on the outside.

the car is a 1995 Z28 4L60E

 

If it bangs when you shift it possibly sounds like a transmission mount/ destroyed bushing.

Also have you checked your cat? Im not sure if it fits your description, but its by the passenger side of the transmission(as you said). When it goes out it will vibrate, pop, and make grinding noises.

 

Make sure that your exhaust is not rattling and hitting the underside of your car. If its loose, it will vibrate while at idle and when you shift. So, check that first. And yeah, look at your cat while you are looking at the exhaust.

 

i got no cats. i dropped my car off at my mechanic's, gonan see what he has to say. exhaust piping vibrating, that makes sense, but it didnt used to happen. Maybe the exhaust mounts are wasted too.