As a sound editor/ mixer, I would recommend that you check your EQ with decent speakers and sub woofer or headphones. My sub woofer often frightens me with the amount of low frequency crud that is on location sync and probably in your recording. You are only getting rid of rumble that you can hear on your speakers whilst leaving a ton of rumble below the audible range of your speakers.
I alway start with a high pass filter to take out signals below 70hz. Then do the notch filter on the rumble you can hear which is commonly around 190hz in a car. It will also suddenly make the dialog sound brighter as the low frequency sound is actually modulating harmonics right up into voice frequencies. If you are going to sound post, make sure you OMFI the un EQ’ed track and let the experts EQ with better tools and speakers.