Some/most filters have a built in pressure bypass, probably wouldn´t be smart to run the flow against the bypass.
I´ve had my external oil cooler hooked up, with and without the radiator cooler. Possible divorcing it from the radiator, could marginally help with cooling. But have had late shifts, with the divorced cooler, in winter (or even cool weather). Hooked it back up to the radiator, to help with warm up (seems to works best at or near 160-180 pan temp.). Much above 220/240 and the oil changes color. Found a VDO screw in (in the drain hole) sender that is in it´s, third XJ. Tranny overheats, I take a coffee break.
In another forum, to kill an arguement, I tested Dexron, through a viscosity tester (tin can with a hole) at various temperatures, viscosity doubles at fairly mild temps.
Most heat exchangers work from top to bottom. Though Chev, often runs the tranny cooler, from bottom to top, for whatever reason.
High speed or hard duty, a tranny temp. gauge seems wise. Most of the auto tranny failures I´ve seen, other than out and out serious abuse (shifting into reverse at 30 MPH). Have been from high temps. (the innards turn black and dark blue). Foaming oil, from high RPM´s and/or heat, doesn´t cool or lubricate, nearly as well.
Learned about auto tranny´s and heat the hard way, autobahn takes it´s toll. Mud pits, will also heat them up quick.
