I suppose it doesn't matter which of the two engine choices you have, more importantly is the heavier the load on the transmission (towing a trailer et cetera) would mean a higher temperature being put out by the transmission because it is working harder, right?
I have the 2.7 liter 4 cylinder and the transmission is the 4 speed auto 340. I added the B&M 70268 remote cooler, changed the transmission filter, gasket, and fluid last year. I put in Pennzoil atf and seems to work well. No slipping. There was a fair amount of shavings attached to the magnets placed on the trans pan before I changed oil the filter.
I do not know how long before the fluid was changed. I was the new owner for just a month when I did the work and was told it sat for over a year before buying it.
The topic at hand, though, is placement of the temp sensor. Yes, I plan on installing one as well. I will install mine on the send line to the cooler so I can get as accurate a reading without having to cut a hole in the pan and get a pan temp reading.
I am seriously considering getting a second 70268 cooler and placing it on the drivers' side of the a/c condensor (currently, mine is installed on the passengers' side of the a/c condensor) of course, connecting the two in series. Getting two 9" procomp fans for both too. I can observe the temp and if it gets too high, just flip the two independent switches for the two fans.
One thing: I'm moving, in June, to western Montana. I don't think I'll need more than one cooler, but I'll be towing a 4X4X8 foot trailer there from eastern Virginia. Maybe just a temp. gauge and fan are all I might need. Not a second cooler.