One addtional comment for 6686L (and any others). remember just MHO

The guages on my EX dash for Oil Temp and Trans Temp are almost worthless for PREVENTATIVE use. They do move very slowly but I can tell you when my Trans was at 210+ (before the cooler) the guage said I was fine and everything was "normal". Most experts agree that elevated temps of the ATF hasten Transmission failure dramatically. Ideal temp is 175 or less. The guage on the dash will only show you as "high or Hot" when the temp hits 225+ (too late for me as the damage has been done).

The engine Oil temp is much the same. I like to see the real number and not just a "relative" guage. The data is there on the ODBII port or with external probes.

D