External Transmission cooler?

[teknik_ranger]

I knew about the heat exchanger being thermostatically controlled, but how often do these fail? The cooling system may have caused premature wear due to the fact that I had to replace a water pump recently. The old one that I pulled off was a re-manufactured and looked to be inferior quality.

I know also that there is a lot of taboo about whether or not it is better to have a stand-alone external cooler or run it through a radiator first. I am just wondering about anyone doing it.

Also, if anyone has...any problems with the shift points because of the transmission temperature sender? I know that when it's cold it has a different program and shifts are a little firm.