My 2004 V70 AWD started to act strange today. 96K miles.

Going from reverse to drive, it felt like it clunked. Check Engine light came on. Then it seemed to go into lower power limp-home mode. I shut off the car, and restarted it. Check Engine light still on, but no longer in limp-mode. The message display says "Transmission Service Required".

Shifting into Neutral seems to put the car into Neutral, but the display still say "D" and not "N". The orange indicator next to the shift lever also goes back to "D" even though the position is clearly "N". Restarting the car, it seems that it might or might not go into limp-home mode. If it does, the display says "-" instead of "D". Regardless, it still has the same transmission service message.

Since this happened this morning, it also seems to downshift a bit hard especially when coming to a stop. It just feels clunky whereas it felt smooth before.

Might it be the neutral safety switch? Something else? I'm hoping it's not a whole bad tranny (though I'm sure if I take it to a dealer that's likely exactly what they'll tell me regardless of whether there's a simpler fix or not).

Thanks for any help!

-Steve