The questions are whether there is a trans fluid that resists foaming better than others or an additive that does that? Is my trans in need of repair?  An unrelated question is is there a trans temp gauge kit made for a Tracker that would easily fit the cooler out line without extra hardware?

I'm not aware of a temp gauge kit specific to the Tracker, in fact, I suspect there is not enough demand to justify developing one, but it should not be too difficult to fit something intended for a bigger vehicle - what you'll need to do is find somewhere convenient in the line to the cooler to fit a tee that will allow the sensor to sit in the coolant flow path.  I used a rather clumsy arrangement with a 1/2" brass tee along with a couple of 1/2~3/8" reducers and 3/8" hose barbs - the 1/2" tee was necessary because I was using a mechanical coolant temperature gauge which had a rather bulky sensor bulb - electrical temperature sensors are typically smaller, but, electrical gauges in the 1.5" size that I like are not easy to find - I had two mechanical temp gauges knocking around, so I used what I had on hand - as long as the sensor tip is in the flow path, without restricting the flow, it'll work.
  As long as I know that I need 3/8 I will just go to the NAPA and put something together Then I can cut the line and slip it in.

Did you mount the cooler before the radiator heat exchanger or after?  There are differing trains of thought on which is better, and also where to sense the temperature - my preference is to have the cooler before the radiator (I want the excess heat dumped into the air rather than into my vehicle cooling system) and the temp sensor in the line from the transmission to the cooler, so I know how hot the fluid is getting.I have it before the radiator cooler and would put the sensor right after the trans outlet to the cooler so I get the true temp. I mainly want to find out if it is heating up or just foaming.

For the fluid, I know Red Line makes a high temp ATF that is Dexron III compliant but I have no experience with the product. Red Line. I will check that out. I couldn't be the only one with this problem.  As long as it settles down I can live with it. I'll let you guys know if I find anything out. I appreciate your help. 

As long as I know that I need 3/8 I will just go to the NAPA and put something together Then I can cut the line and slip it in.

Which transmission do you have - 3 speed or 4 speed?  The line is probably a 10mm close enough to 3/8" that you can get a hose on it - if you're using metal compression fittings you could run into trouble.