I am considering an auxiliary cooler for my automatic transmission. I have seen the write ups and read as many of the threads as I could find and I am convinced that heat is the enemy of these trannies. My question is will it be too cool in the New England winters.

Background: this is my first automatic so I am pretty ignorant about them. 2-door, stock '08 Rubicon, light wheeling for now because it is my DD for another year or two. I do not tow. I plan to keep it for a long long time (I hope) and plan to mod and wheel it harder, so I want it to age gracefully....

I am going on a long road trip later this summer to Montana/Idaho so I'll be racking up some serious highway miles getting there and back not to mention the mountains out there. A transmission cooler is probably a good idea but...

What about winters back home? Can the tranny be too cool? I read about problems where the fluid won't flow so the tranny actually overheats. Should I worry about that? This is NE, not Alaska, so I won't see more than a few sub-zero 'F days.

Any advice or opinions? Thanks!

 

The tranny fluid will flow at 15 degrees F. I know this because I was stupid enough to change the filter on such a day last winter.

I had a tranny cooler in all last winter with no problem. However, I don't use the cooler fan during the winter.

It was stated in another post that the tranny needs to hit about 82 degrees F for the TC to lock up. So that should be your biggest concern. I can tell you that I had no problem with this all last winter.

 

Since the torque converter won't lock up until 82 degrees the slippage of the converter will put heat into the fluid pretty quickly.

Heck if you've got a gauge monitoring the transmission and it doesn't get up to around 100* or so then you can always cover the add-on cooler to keep the heat in it or cover the factory cooler during the coldest of winter months - doesn't need to be fancy - a simple piece of cardboard will work - and if it's that cold the blocked airflow through the radiator won't make a darn bit of difference to engine cooling either.

 

The cooler I installed (and that is in my writeup) only passes the fluid through the entire cooler when the oil temp reaches a certain temp. Its perfect for cold weather climates. Its a B&M cooler.

 

Link please

 

https://www.jk-forum.com/forums/jk-write-ups-39/transmission-cooler-37839/

now send me a dollar

I put in the 70264, its a little bigger then the 70268, I think it was 2000 more btu or there abouts. My temps run anywhere from the 130's to 185 at most now, lower since I put new bumper on and have the winch mounted down in it instead of riding on top of bumper blocking airflow. Also I have the aeroforce gauge which gives digital read out of the temps I'm down in GA and had the a/c on for first time in long time and I was running 135, its 95 and humid as hell haha.....btw the trans temp gets up there pretty quick, I was running 208+ before I put the cooler on

 

I installed a flex-a-lite 26,000 GVW cooler over a year ago. I've put 25,000 miles on my rig, NO issues.