Installed a tranny temp gauge - Observations / Questions

I just got a rebuilt tranny installed in my 95 GMC Jimmy 4X4. So, after sinking a lot of money into it I wanted to keep tabs on the fluid temp since I know how it impacts the life. There was an aftermarket cooler installed in front of the radiator. And I put the sensor in-line of the rubber hose that goes to the cooler. It is sensing the oil before it passes thru the cooler. I have had it in for a few weeks now.

So , here is what I have noticed. If I hop on the highway with the car cold the fluid stays under 140F.

Anytime I can get the truck faster than 50mph it will start cooling the fluid. Does that have to do with the torque converter not being used and the additional airflow over the cooler?

This is what concerns me...how hot it gets in stop and go traffic. We had a few days above 90F. I was in about 4 miles of stop and go with nothing over 40mph.

The tranny temps started climbing from a comfortable 150F to almost 200F. This was just in stop and go traffic. It was a bit startling because I have never seen it climb that fast or that hot. What can you do in stop and go traffic to keep it down? Put it in neutral at the stop light? Rev it up a little bit?

According to this chart I am fine for temp limits. I would not imagine what the temps would be if I was towing. OR if I was still using the in radiator cooler. HOW IN THE HELL does that even COOL the fluid? I would think that would heat it more than anything. Scary.


http://www.tciauto.com/tech_info/images/trans_life_expectancy.jpg

Here is the gauge I am using:
http://img.photobucket.com/albums/v238/rotaryr/EBAY/tempgauge.jpg
I will post some pics of my install when I get home in a week.


James

Well basiclly the heat is a result of slippage. Stop and go results in more slippage of the clutchs as its shifting up and down all the time. The tranny cooler needs air to be passing through it to be effecient. In stop and go, you don't get to much constant air getting through it. To solve the stop and go problem, you can install a separate mini fan just for the tranny cooler. But at around 200F your are fine.
Also, the torque convertor is always used. The difference is when your at cruising speeds its locked up, and when its locked, this results in no (very, very little) slippage of the convertor, less (or no) slippage = less heat.