Hello All,
I have the 5AT RE5R05A (I think?) in my 2008 G37. A couple of days ago the tranny all of the sudden started shuddering fairly violently for 1-2 seconds when shifting from 2nd to 3rd gear. I've only had the car for about 6 months, and thought I could feel a little vibration when shifting into 3rd in the past, but is was subtle.
I checked the fluid, and it was a little low, so I added about half a quart, but same results.
There does not appear to be any coolant in the fluid, and no fluid in the radiator.

Any thoughts on this? Should I go after the valve body or tranny itself? There isn't squat for info on the web about common failure modes for these trannys which I thought was unusual.

Not really sure where to start. Any help would be appreciated. Thanks!

 

Have you checked the FSM for the correct procedure to change tranny fluid?

 

Check your battery if it has any loose connection. I had a issue with my 08 coupe transmission shifting very weirdly by jerking hard and had a rough start, went to mechanic and he fixed it by tightening battery connection.