Re: Transmission Temp
Form my diesel truck experience, the tranny temp should be 60-80 degrees above ambient temp. That's just a rule of thumb and certainly may not be exact for a mid size SUV compared to a 3/4 ton diesel with a matching tranny. However, the 66RFE is supposedly not that far from the diesel Ram's 68RFE, but that also does not account for a much larger tranny cooler in the Ram as well.
Tranny temps rise quickly in hot weather, towing, or moving at slower speeds, or all three conditions simultaneously, but should cool down as speed increases and air rushes through. IF you are moving too slow or towing in hot weather, drop to a lower gear to run the engine faster to pump fluids and air. Lugging the tranny is also detrimental. Unfortuntately, I have not seen deep tranny pans like those for trucks. Aftermarket tranny pans can add an additional 3-4 quarts for better cooling and cooling fins.The best way is having a tranny cooler installed---the outside coolers work better than the combined radiator/tranny set ups.
Again, rule of thmb is keep that tranny below 220. Anything over 250 for more than an hour can start damaging the tranny. Heat kills.