I have a 2001 F150 4WD supercrew and the transmission light on the dash is coming on with the gauge dropping to zero and after a second or two the light goes off and the gauge goes back to normal. The fluid level is normal and there are no other issues with the tranny. This happens while idling or at very low speeds. It does not matter if the temperature of the tranny is cold, warm or hot.

Any suggestions as what the issues is?

 

I didn't know there was a transmission gauge and light - you sure you aren't talking about the oil gauge and light? Check your engine oil, if it's not low, you probably need a new sending unit. It's screwed into the block right next to the oil filter.