I've run and installed dozens of coolers, particularly back when I was in the trailer hitch building business. Unless you're anticipating doing a lot of driving in below-zero temperatures, I see no need for a bypass system. The in-the-radiator "cooler" is going to bring the transmission fluid up to thermostat opening temperature within a short time anyway, so if you're concerned about cold starts, the temperature of the trans fluid will approximate coolant temp on even relatively short trips. Most transmissions can operate pretty trouble-free if the fluid temp is kept below 250 degrees or so, and I don't think there's a low temp limit at all. A manual bypass system can be fabricated with two 1/4" NPT ball valves and a little bit of steel gas line tubing if you want one- - -no need for an expensive kit from somebody!
Jerry
Last edited by Hotrod Lincoln; 10/28/2010 2:20 PM.
