I'm experiencing significant vibration under acceleration at highway speeds only. Goes away when you let off the gas, so its not a wheel or tire. My mechanic checked all the usual suspects, CV axles, etc... He thinks its the transmission and said I should bring it to the dealer.

So, am I looking at a transmission replacement or could it be something smaller? I'm beyond the warranty unfortunately. I know Nissan extended the transmission warranty for other models, but don't think they did for the Quest, right?

- Greg

An engine mount can do it. Pass side likely.

...not for the quest unfortunately (re warranty). Some people posted about having nissan cover the replacement cost - not for me.
Good luck,I hope it’s something else

Update. One of the wheels was out of balance casuing the shimmy at 60 mph, but the transmission was ALSO going. I have 82,000 miles on the van. After calling the 1800 Nissan 1 number, Nissan covered 80% of the replacement cost. I was surprised and satisfied.