I'm the second owner of my 2005 Infiniti FX35 AWD which has 160,000. Recently had major maintenance done including coolant flush, gear oil changed in front and rear differentials among other things. In the last month I've had an intermittent issue (occurred twice) that I've not encountered since I purchased my FX35 4 years ago.
When I drive over 40 mph, the entire car starts shaking almost as if the wheel were about to fall off
...I notice that the gear shifter for the transmission is moving back and forth with the shaking quite a lot when this happens as well. At first I thought maybe it was a wheel weight that flew off and threw the wheel way out of balance, but they the shaking stopped after that drive and didn't run into the issue until a month later.
Any help is greatly appreciated. Thank you