For the past few days, i've noticed that when I shift into 4th, my shifter vibrates while my hand is on it. I'm not really low on RPMs either. It's never happened before and I thought I was kinda weird. Three weeks ago, I replaced my tranny fluid. Is there anything I should be worried about??

 

What did you use as a replacement tranmission oil?
(Other than asking, I'm not going further down this slippery slope. I'll stand back and watch this debate fire anew!)

How much did you put in? It takes ~2.5 qts to fill the trans.

 

I took it to the dealer to get the transmission serviced

 

I did my own replacement and never had any issues after doing it, other than the transmission shifted better after the change. But I used Redline MTL rather than Honda MTL, since I did it myself.

My suggestion would be to go back to the dealer and bring this to service departments attention.
It could be that the shift linkage needs an adjustment. The shift arm for the transmission sits next to the refill plug and, depending on how the tech went about removing the fill plug, it's possible something got out adjustment. That shift arm has to be moved out of the way to clear the filler hole.