EV performance Trans Temp.

I was driving the other day (truck not warmed up yet) and noticed the trans temp gauge fluctuating back and forth from 160-280...

It only did it a few times.. i got to where i needed to go. Got out checked the fluid to see if it was hot.. seemed fine. got back in and it stopped.. but about five miles downt the road it started doing it agian. Trans is shifting just fine.

Is the gauge just busted and i need a new one? or just one part?

Gauge is about a year old.

Thanks

Which series gauge is it? Is the lens flat or slightly curved? Does it have an amplifier box under the dash, an ESP under the hood, or no box at all?

Thanks,
Michael Pliska