I have read that installing a aftermarket trans cooler will possibly void factory warranty, Would it be possible to install a aux fan in front of the ac coil. You could switch it to turn only on trails, That couldn't be a problem for warranty right? Would that be enough to help the problem?

 

See if the dealer will install an additional cooler. migt be pricey.

 

You'd be better off with a switch to turn on the regular factory installed fan.
A fan installed in front of the condenser will not force air through the tiny transmission cooler at the very bottom of the condenser.

 

Just a warning but if you take it to the dealer, make sure they do not just remove your transmission skid plate and say you are good to go. That is how they fixed the issue on 11's. They replaced the skid plate with a skinny bar that won't protect anything. I have heard they have done this to previous model years when they have overheating problems.

 

Strange they would do that, when their own factory service manual says to add a transmission cooler to remedy overheating issues.

 

Yeah tell me about. I am not the biggest fan of Chrysler right now!

 

I had a transmission guy tell me there was no way any manufacturer could claim a tranny cooler cooked a tranny. He said it is proven fact that heat kills auto trannies and adding a cooler will only extend the life of the tranny. Even if they try to void your warranty you are much better off running a cooler.

I have heard that in really cold climates you could run a cooler that was too big that wouldn't allow the tranny to warm up enough. This particular transmission guy told me that if you keep the stock cooler in the loop the heat from the radiator will allow the tranny oil to sufficiently warm up in all but the coldest climates. So, unless you are in upper Alaska I would put a cooler on there and not worry about warranty issues.

A lot of transmission shops won't warranty transmissions that don't have an aux transmission cooler.

 

The heat from the radiator makes no difference to the transmission fluid temperature in the JK. The fluid does not enter the radiator as it does in most other vehicles.

 

The oil on the diesel auto, does go into the bottom of the rad, which is meant to help keep the oil at a more constant temperature, I would prefer a water to oil cooler, so no fan needed, and again more constant temperature.

 

Thanks for the info on the diesel/auto transmission cooling.
With the low number of diesel JK's in the U.S., and the fact nobody in this thread mentioned having a diesel JK, I felt safe not specifying gasoline powered JK's only.

The water in the gasoline JK runs as high as 215°F, so I'm glad the transmission fluid doesn't flow through the radiator.