2009 Civic - NVH problem, transmission related?

[Howard]

Also a burning smell from time to time.

https://www.youtube.com/watch?v=Fw0-saQ1o7Q (louder in cabin than the video would suggest)

It's pretty loud when reversing, and also pretty loud when coasting at speed. Accelerating makes the noise go away. More details to come.

 

[NutBucket]

My initial observation is the engine is cold so it's idling high to warm up the engine. All cars do this. Putting it gear lowers the idle because the torque converter is loading the engine.

 

[The Stigenator]

engine's cold. Wait for it to warm up before you do that. The RPM drop is due to the torque converter as nutbucket says, the engine and transmission are engaged.

If its idling high when warm, you got a PCV valve leak or a vacuum leak.

 

[Howard]

I'm told it's getting louder and louder, especially in reverse. Warming up the car doesn't solve the noise issue. Lots of rumbling and such.

Not a lot to go on here, but it seems louder than normal.

 

[HitAnyKey]

Disclaimer: I am not a mechanic but I have had many cars and this is how I would approach the situation.

Here is the list I would start with:

1. PCV Valve
2. EGR Valve
3. Check spark plugs and wires for clean operation
4. Check Battery and Alternator for proper operation
5. Transmission fluid and Operation
6. Check radiator fluids
7. Entire exhaust system including the Catalytic

Failing that switch brands of gas and give a good run on the Highway (at a responsible speed) to see how she drives and if any hestitation, backfiring or high gas useage.

Good luck