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transmission cooler

CROSBIKE

NAXJA Forum User
Location
Fish Lake UT
ok so i have a transmission cooler that im going to install and i have a question or two. The directions say i can run the lines straight to the cooler and back to the tranny and cap the radiator off. Or i can run through the radiator to the cooler and back to the tranny. Im thinking the second option is better because there is more area to cool the oil before returning. what do you guys think? any opinions are greatly appreciated.
alex
 
What is more critical, water temps or trans temps?

If you abandon the radiator it will give the water temps better cooling (cant document how much). The trans will be 100% reliant on your aux cooler so it better be at least as good as stock.

If you choose your second option, the water temps will be no better off but the trans will be cooler (total cooling ability).

If you choose option three (aux cooler first, then radiator) the water temps will be better and the trans will be better. Optimum solution would be to keep the aux cooler away from the radiator stack but I havent solved that one yet.

I have seen trans temps go up and drag the water with it. The water temp will never go below max when the trans is above 220.
 
Take option 2. The factory trailer towing package uses that method. The factory aux cooler is pretty big and it goes through the radiator also. My water temp has never passed the 210 mark. Even in parking lot Moab traffic/wheeling with the windows up and AC on. I don't have a tranny temp guage...So who knows there.
 
i don't know how hot my tranny gets but i hooked straight to the cooler and back.bypassed the radiator altogether.mine does'nt get above 190-200 EVER!!! with the ac on in 4x4.(ya know,in the snow uphill both ways!)hasta
 
What size cooler you guys running? I'm wanting something kinda big, lol. B&M still a good choice?
 
I believe that I would still run it though the radiator. Having the trans fluid too cool can also be a bad thing. Running it through the radiator makes sure that the trans heats up in a timely fashion, and that the aux cooler won't be overcooling the fluid in the dead of winter, as the radiator will transfer heat from the coolant tot he trans fluid.
 
Installed a B&M on the wife's XJ as we tow a utility trailer on long trips. I used option 2 for the same reason passxj did - Just like the factory tow option.

Tranny -> Rad -> Cooler -> Return

No tranny issues whatsoever, but sometimes there's some rough idle/heat soak at the end of a 13 hour non-stop drive towing 2500lbs.

I'm sure the 3rd gear highway RPM has more to do with it than tranny temp, since she drives it everyday with no issues, and there's never a problem on shorter towing trips.
 
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