Early on not long after purchasing my Jeep CRD, I added a Derale 10 plate stacked transmission oil cooler in series (after) the OEM cooler to help control fluid temperatures when towing loaded trailers. I mounted it in the opening below bumper so as to not add any additional heat into the OEM radiator stack. I also installed a transmission temperature gauge with a sensor using a Tee block on the metal oil cooler outlet line before the factory cooler so I could monitor fluid temperatures leaving the transmission. When under load pulling load up long hills, the temperatures still wanted to creep up above 220 in the very hot sunny south (100 deg days)
So next I purchased and installed a cast aluminum PML deep sump oil pan that has large cooling fins both inside and outside of the pan to help with heat dissipation. With the addition of the PML pan along with adding another temperature sensor in the aluminum pan's sump, (it comes drilled and taped for a temperature sensor and a drain plug).
The PML pan was the icing on the cake, after the install, no matter what load I was pulling during high heat & humidity conditions, I never saw any fluid temperatures rise above 200 degrees even on long hills on the hottest days. I added a switch so I could switch from one fluid sensor to the other to be able to monitor the hot fluid going to the coolers, and the fluid sump temperature. About a 20 degree difference when working the transmission hard during towing.
The deep sump oil pan allows the addition of several more quarts of ATF+4 along with the cooling fins really helps control temperatures.
And, if you pull or replace the transmission oil pan, get a "LUBELOCKER" pan gasket, best I have ever used, has silicone impregnated into the gasket and is reusable.

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Supporting Vendor and Moderator of LOST05 Jeep Liberty CRD Limited 
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