Transmission Cooler Recommendation and Installation Instructions for a 2007 Jeep JK 3.8 Liter

Published 05/11/2011

Products Featured in This Question

Derale Series 8000 Plate-Fin Transmission Cooler Kit w/Barb Inlets - Class II - Efficient

(872)

$88.31

Derale Insta-Dapt Radiator Adapter

(5)

$8.92

Derale Series 8000 Plate-Fin Transmission Cooler Kit w/Barb Inlets - Class III - Efficient

(872)

$94.69

Question:

Vehicle: Jeep JK 3,8l, AT, no AC plan to tow 2.000lbs travel trailer, would use locatio #1 ahead of radiator. Is this cooler the best option. How do I plumb the lines to the transmission? Is there a flow direction that should be considered? Hose routing any pre-cautions?,Which is the return line? Upper or lower line to the original cooler connection?

asked by: Karl

Expert Reply:

The Derale Series 8000 Plate-Fin Transmission Cooler Kit, item # D13501, is a Class II efficient transmission cooler and would definitely help the transmission on your JK, but since you are towing 2,000 pounds I would recommend a bit larger Class III cooler like the Derale Series 8000 Plate-Fin Transmission Cooler Kit, item # D13503.

You cannot cool transmission fluid too much, so the Class III cooler will provide better cooling when towing and will be good for the transmission around town also. You just need to make sure there is room for installation of the Class III Cooler in the # 1 location in front of the radiator. There should be plenty of room on your Jeep, but check to be sure.

You will plumb the transmission cooler inline on the transmission fluid return line. The Insta-Dapt Radiator Adapter, item # D13004, will install in the radiator port and then the rubber hose is clamped to the male fitting. the other end of that hose is attached to the trans cooler. Next, attach a second length of rubber hose to the other transmission cooler fitting, then, clamp the other end to the transmission return line.

expert reply by: Robert G

Karl

5/11/2011

Bob G.

5/11/2011

Glad to hear from you again. To find the return line, start the engine and let it run for a minute or so. Then shut the engine off. Now feel the two transmission lines. The coolest line of the two will be the return line. Normally the lower one, but not on all vehicles. Performing this test will tell you for sure. If conditions are warm out you may need to run the engine a bit longer to distinguish between the two lines.