Coolant leak cant find it . it only leaks when heats up and it has a heavy drip coming out where the transmission meets the oil pan undernearth

Could be the pan gasket for the transmission anyway. Remember that the wind caused by the car motion and the angle the car is parked at can change the direction from which the fluid runs. You do not want to replace the front transmission seal (additives may seal) but a transmission pan gasket is much cheaper.

It is normal for more fluid to leak when the fluid is hot. Some places like Midas or Goodyear outlets may do transmission filter changes.

A couple of leaks can be fairly large. An Oil Pan leak where you will see oil seeping down the sides of the pan and dripping directly below. The other is a Rear Main Bearing Seal leak and the oil will be coming from where the engine meets the transmission.

Normally if oil or transmission fluid mixes with coolant it will turn milky looking like a milkshake. Your leak must be pretty fresh. from your description that it is coming out of the coolant overflow I am thinking you have a radiator transmission cooler leaking into the cooling system.

You will need a new radiator and possibly all the coolant hoses if they have become soft from the transmission fluid.

In most cases if your getting transmission fluid in the radiator it is cause by a bad transmission cooler that is built into the radiator and the fix is to replace the radiator.

The repair will change in price from where the leak is coming from. If the pan is leaking or the rear seal your looking at $100.00 or less. If the front seal is leaking then around $550.00. The most common leak is the pan gasket. Also if the transmission fluid and filter have not been replaced in the last 30,000 miles and the pan is leaking then I suggest doing this also why the pan is off .

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

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TRANSMISSION FLUID LEAKS,CAN BE FOUND AROUND PAN GASKET.CHECK PAN GASKET,IF IT LOOKS WET AND YOU SEE FLUID DRIPPING AROUND THE EDGE OF OIL PAN, REPLACE PAN GASKET, WHILE YOU REPLACING PAN GASKET REPLACE TRANSMISSION FILTER WHILE OIL PAN OFF.IF TRANSMISSION OIL PAN NOT LEAKING, CHECK TRANSMISSION OIL COOLER LINES GOING INTO RADIATOR YOU WILL LOOSE A LOT OF FLUID THERE ALSO TORQUE SHAFT SEAL WILL CAUSE HEAVY FLUID LEAK WHILE ENGINE RUNNING CHECK OIL COOLER LINES AND LOOK AT THE TORQUE AREA WHILE ENGINE RUNNING YOU WILL SEE FLUID POURING WHILE ENGINE RUNNING THE OIL PUMP PRESSURE WILL PUSH FLUID OUT AT THE LEAKING AREAS.

Is it leaking FROM the oil pan, or dripping OFF the oil pan?

If its dripping OFF the oil pan, that leads me to beleive you have a coolant leak somewhere. Check the coolant level. Check for leaks.

Check your oil, if the oil is milky/coffee colored. Or if your coolant looks kinda nasty, you may be looking at a headgasket.

There are three places above that pan that the leaks could be coming from. 1- Tail shaft of the transmission.Would be a red color. 2-3- Input and Output shafts on the transfer case. More the color of motor oil. There may be more oil in that skid pan just not at the correct angel to let it run off.

First you need to identify what's leaking? What color is fluid? Green, Red, Brown? and where under car is fluid leaking from center, front rt, etc... Another option is check ALL fluid levels - coolant, oil, power steering, transmission.

It' s a guess. First I would for any engine frost plug leaking. If equipped with a block heater check it for leak (depending where it has been installed).
If I'm wrong let us know and we will go further.
Hope it will help
Dan

where is it leaking from now / get it real clean and let it dry then crawl under it and look for drips / no drips then start engine and watch for leaks if you cant tell where it's coming from try with it clean , throw flour at it , any leaks will make the flour wet and you'll see where it's leaking from . the speedo ? the pan gasket ? the end seals ? the breather ? the lines ?
you want to save money , get under it and find the leak then do your fix

Likely what you are looking at is where the coolant is dripping, not where it's coming from. I have no idea why if you have an external leak, that it somehow is getting back inside there to get into the oil.(pretty much impossible)
Best guess is that you have a bad water pump that is beginning to leak. If in fact you have coolant in your engine oil as you say you do, most likely cause for that is a blown cylinder head gasket.
If you actually have no idea what is going on there, have a good shop look at it. Leaks lead to overheating which can cost you an engine.