Trans temp

Its a sliding scale on temperature v. trans oil life. Here's one:

http://www.txchange.com/heatchrt.htm

Generally over 250 degrees is your limit on trans temp as that starts to degrade the oil. Synthetics can take the heat a bit better, but they still have a limit. The longer the oil is at that high temperature the higher the chance of eventual failure. I would stop and idle the engine in Neutral for 10-15 minutes to try to cool it below 230 before moving on.

On all my vehicles with Auto transmissions, I try to keep them under 200 on normal type days (80's). Even added a larger cooler to our RV Allison transmission when it started running 230 on easy roads in the 80's and low 90's.

That question is subjective..

I added a large trans cooler. Towing to florida to disney I saw cruising trans temps no higher then 165F. Traffic maybe 175F.

This is with A/C on and 96F outside temps.


My weak factor was pulling 5330 ft up the NC smokeys. Coolant temps ran up to 230F but trans maxed at about 190F

Hers a 75 mph cruising pic from my scan gauge.

https://flic.kr/p/WwFgxp

Op here. Highest I've seen was 179' was on our last trip. Pulling
some 18 degree hills along the st Lawrence in Quebec. So I guess that wasn't too bad then.

It very important to know where the fluid temp is being monitored. Coming just out of the pan into the torque converter it will be coolest and coming out of converter it can be 100 degrees hotter.

Mine has been up to 225 F on a 10,000 pass in Colorado.