97 accord, DX. Whenever speed is higher than 60 mph, a low pitch popping sound is from somewhere under the hood. The car is still drivable but i feel very uncomportable with the sound. It is also looks like that there is no such sound when it is in parking and runs at same engine speed, so i am thinking that the sound is not from engine, mounts orbelts.I hope it is not the problem of the transmission since i know it will be expensive to repair. But i did have changed the tranny recently, no flushing, just change fluid. Anywhere else could be the source of the popping sound? Could it be tires? But they are pretty new, less than 10k.

BTW, last time whenI changed the tranny, saw lot of oil on the bottom of the tranny pan. checked the tranny level several times but did not observe apparent dropping.

 

The noise only comes out when I depress the gas padel. Timing belt? Intake? but why it is not there when no moving?