I haven't had any problems yet with my tranny, but will definitely be adding a tranny cooler. What I am not sure of is what one to get. I am looking at the the following:

BM 70268 - seems to be the most popular on JKF - 13000 BTUs
BM 70264 - Also used by a few - 14400 BTUs
BM 70266 - 20500 BTUs

Given the fact that I live in Tucson (HOT) and use the Jeep primarily off road for slow speed fun, which would be the better option? I expect the one with the higher BTU would be better for the tranny.

However if I am doing a lot of slow speed crawling, will even the 70266 provide enough cooling without a fan? If so, I would rather not make this more complicated and not add the fan.

Should I consider just getting the 70268 with a fan? The 70268 is about 3/4" and the fan is about the same width. The other two are 1.5". Not sure if the 1.5" coolers plus fans (3/4") would fit.

Suggestions? Thanks.

 

I'm running the BM 70268. I'm in the Phoenix area so I can relate to HOT (115 F = HOT or Damn Freakin' HOT?)

Transmission will still get hot if you run long, steep, slow-speed climbs in Hi range - maybe up to 20-25 MPH. Faster than that is never a problem. Turning on the A/C will force on the fan and helps a lot, but the engine can get hot after a bit.

4-Lo is never a problem. I never have overheat issues when crawling. On the long climbs, slowing down and putting the transmission into low-range for a bit cools things off in a hurry.

I have the Aeroforce scan gauge so I always keep a close eye on the engine and transmission temps.

 

slow crawling in the desert heat... I have to think you want one with a fan.

There is a lot of room in front of the radiator. Try a empty shirt box or something similarly sized to test fit the space.

 

Mines a derale 13613 with a 7 inch fluidyne fan. It has a thermostat switch and runs off a relay. 22,500 gvw rating.