texangator

Yesterday it rained heavily in Houston and I drove over some flooded road patches that resulted in water hitting the bottom of my car with high pressure. Anyways, I made it to work but when I drove the car in the evening, I noticed this weird noise that is similar to the one that would come from a burst silencer. Here are some specifics.
1. When I start the car in 'P' mode, it starts fine but immediately after it start I can sense the change in sound. However, it is not that bad. If I increase the RPM, the noise increases a bit but not that much.
2. As soon as I put the car in D or R, the noise becomes louder.
3. When I start driving, it becomes louder but it would intermittently go away and complety goes away at speeds greater than 40-50 MPH.
4. It is louder at slower speed (like 10 MPH) and if I switch to N, then it goes away,however when I push the accelerator while at N, I still still hear it though its not as loud as when the car is in D or R.
5. The RPM at P or N are around 600 and when I put it to D or R, it is around 400.

Any ideas of what could be wrong here? Is it safe to drive the car with such noise coming?

texangator

Oh, and one more thing. When at 'P' and I push the accelerator over 1000 RPM, I can feel a bit of vibration too.

fastryan

we have no idea what "sound " you are referring to. need a vid or sound bite. or even a sound description. what does a "burst silencer" sound like?

texangator

Sorry about sound description. The sound is similar to the one that would come from a leaked exhaust pipe. Also, when I shift the gear from R to D, though there is not clunking noise but I do hear a slight thud - is that normal? I think it has been that way since I had the car since about 6 years ago.

ebxgsxr

my transmission mount was just about completely separated, but i never heard a sound like that.

texangator

I also noticed that if I am in 'P' mode and turn on the AC, I can hear that sound. I think this has to do something with the mount, either engine or transmission. My mechanic said the tranmission mount is broken - so I will start with that.

shvc1991

I would replace the engine mounts too if I were you. If your engine mounts are shot and you replace only transmission mounts, the transmission mounts will be ripped apart in no time.