Weird problem that I've just noticed. I changed my oil gauge sender unit recently. Now today is the first time I have had the car on a highway since the motor rebuils and so the first time I got all the way to 5th gear. What would cause my oil gauge to stop working when I shift into 5th gear. I mean the meter reads like it is not connected. In any gear it reads between half to near full scale depending on revs but not in 5th.

Any ideas, did I cross some wires between the oil gauge and tranny switches???