Without knowing who made the gauge,since it already has failed your only option will be to buy one from one of the othe gauge companies.Ive had good luck doing that in the past
Barry hit the nail on the head.Gauge is a US Gear... it's a 3 gauge pillar mount. Trying to not have to get a whole new set because of just a trans temp sensor. Be nice to see if there's a replacement sensor to put in its place.
I think bob4x4 was referring to just the sender from someone else. Autometer and others do sell just the sender. Might be worth a call to one of them like autometer, isspro etc they might be able to give you a line on one of their replacements that would work as a replacement for your current sender.