Transmission over temp display. what does this mean?

That really depends on what year model and make the vehicle is. I don't run thermostats in older vehicles like 95 and down and they do fine

Maybe a thermostat..or the heatercore clogged up..If the vehicle runs hot pretty quick then its the thermostat stuck closed..If the vehicle is not running hot,but you have no heat then the thermostat will be stuck open or the heater core not circulating

Thanks for choosing FixYa and welcome to the site. They all are right. Anyone of those parts can cause overheating. The most common issue is the thermostat though, followed by the water pump. You could have a defective coolant sensor. If you have a bad head gasket, it will cause overheating. If you change the water pump, change the valve and the impeller also. Do this. Check your coolant level first and make sure it is level. You said fans are good. Make sure the radiator is good and is getting fluid inside it. Make sure there are no leaks. Check all coolant hoses. Like I said, the most common issue is a sticking thermostat or a bad one. Next, I would say the water pump.

Make sure that your thermostat is working correctly. Let the engine warn up, not long enough for the vehicle to get into close loop, but to where the hose is warm. At this point the hose should be hard. If it isn't hard you will also hear the water flowing as you squeeze it. Often the thermostat goes into a fail safe mode which is all the way open and with the engine having run hot, this could have caused failure here. If it does't pass this test, it should be taken out and looked at. If it is bad you will see it all the way open...you can always compare it with the new one.

I'd still check the thermostat. Or basically just replace it. Have you ever drained all the antifreeze and flushed the system? Good time to do both. If the hose's get real hot that doesn't really mean the thermostat open. Wouldn't they get hot even if the thermostat didnt open.? If the thermostat was stuck open you'd would have cold air and low temp gauge. Then maybe hit a pump or something and have the thermostat stick closed and have high temp. Maybe water pump. Check it when you have the belt off. Spin, pull & push the water pump pulley around. I'd replaced my water pump at about 110,000 on a '97 dodge Dakota. My 97 never had a very good heater. Always heated up more after driving. Idle never got it warmed up.

Remove thermostat and run the vehicle. do your hoses get tight now? If so, your new thermostat was not opening up. test it by putting it into a pot of water and bring up the temp on your stovetop. if the water boils, and the thermostat isnt open, then get a refund and a new thermostat. Be sure to point the spring end of the thermostat into the engine block when replacing. If your thermostat did open, then your water pump may be shot.

Then replace the thermostat, because if on lower hose not hot and on upper hose scalding hot = antifreeze flow blocked by the thermostat wich remains closed!!!

Thermostat replacing:

have you replaced yor thermostat? have you checked your radiator cooling fans to see if they are coming on while your car is heating up? when your temp. guage is halfway up your fan should come on. you can check fuses and relays in fuse box[black box under hood drivers side] check those to see if fuses are blown or if fan relays are coming on[ticking while engine heating up]radiator could need flushing out also, just narrow your search some by elimination. if you open radiator cap before you start engine,then start motor, let it warm up.look for circulation,,flow of fluid,bubbling, then thats a sign it's circulating,thermostat is good. no flow means that thermostat not opening,thats bad thermostat.replace the thermostat.if not that are fans coming on? when engine at mid range on temp. guage does fan come on? if not check fuses @ fan relay. if fan comes on ,it's good.check water pump pulley for wobbly pulley while motor not running, shake pulley back @ forth for play. any play in pulley means bad water pump. are the belts on? i went through everything i would look for myself. hope this finds your problem!!!!

Could be thermostat, temp. sensor, or degraded coolant(Water will boil, cars need coolant.

there is a sending unit for the guage.but if it has been running a few minutes and gets hot you may need to check the thermostat or water pump.check the water pump by taking the radiator cap off.then start the vehicle,look into the radiator and see if any coolant is flowing or circulating.do the cheapest fix first