DougE wrote:
If you search some you will find most sources state that the design operating temperature of automatic transmissions is 175*. You will also find that most life vs. temperature charts for auto transmissions do not go below 175*. This is the reason behind installing an auxiliary cooler prior to the radiator cooler. This allows cool trans fluid to be warmed up to the correct temp as the outlet of the engine radiator is ~175*.
Yea, there is a trans temperarture chart floating around the internet that's been wrong for ten years. There is no "normal" as long as it stays within the temoerature range where the fluid is designed to work. See my post above.