Car Runs, RPM gauge at 0.

My 2009 Aveo5 started to hard shift and then what seemed like either more hard shifting twice rapidly or engine stuttering [not sure which one] and then the RPM gauge shot down to 0-RPM and wouldn't move. Shut car off, and turned back on. RPM gauge is still at 0. Idle seems to run fine [from what I hear] and car shifts and runs fine other than the RPM gauge being at 0-RPM after the minor engine/tranny shaking. I do need to flush the tranny fluid, but I do not believe the RPM gauge is anyway tied into the transmission. Any answers as of what that could be?

Thanks.