Need some expert advice on Trans Cooler

Hey all, I'm kind of new here, I have a 2002 3.7 and it has 125K miles on it. On hot days, like now in summer, after any drive over 10 miles on the parkway at constant speed of 55+, I notice that when I get off and resume normal stop and go driving, it seems to shift extremely hard into first when I slow down to stop at a light, or there often is a delay to dropping all the way to 1st. I will slow down and stop and then after sitting there a couple seconds it will kick down into 1st hard and make the liberty a jerk forward. Obviously it doesn't go anywhere with me holding the brake down but this and other odd shifts occur, but only on warm days. Local shop told me that after long drives that the trans temp may getting too hot and I would benefit from adding a larger trans cooler.

I'm aware that the 02' has the integrated trans cooler in the radiator. Would buying a external trans cooler and adding it to the loop be a hard or easy DIY job? Additionally, if you have heard of this quirk before and know that it is being caused by something different can you please advise. I'm just trying to keep this old girl running as best she can without putting substantial money in her. I really appreciate any help anyone can provide. Thanks all!

When I was having trans temp issues with my 2012 liberty I added a temp gauge, an auxiliary cooler and a mechanical fan. The gauge can be had on Amazon along with the compression fittings that you need to add to the hard lines for around a hundred bucks and it’s a very easy project.

GlowShift 3/8" Transmission Cooler Line T-Fitting Sensor Adapter - Universal Fitment​

search for this and it will lead you to gauges as well.

I got a trans cooler kit from oreillys, it was fairly cheap and the hardest part was routing the cooler lines, I had to cut some plastic out of the fan shroud. Very easy project either way.

If you want to throw a couple hundred bucks at the issue this seems like a reasonable thing to try and it wouldn’t be that difficult. I did this to my rig as a precaution. In my experience once an auto starts acting funny it’s already too late though. Good luck

Just to clarify my issue was overheating while off-roading in the summer. I didn’t have any shifting issues.

Rokk said:

Just to clarify my issue was overheating while off-roading in the summer. I didn’t have any shifting issues.

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Thank you so much, I really appreciate it. I think I am going to go with the aux trans cooler, the cooler lines seem pretty easy on the 02' as long as I get some good connectors and hose clamps. This only has occurs during hot days, so hopefully this will cool it off enough. I've also heard of having early model Liberty's relearn shifting by removing battery connections and standing on the brake for like 5 minutes until you have attempted to drain every bit of energy out of the vehicles capacitors. Then reconnect, and make between 40 and 80 accelerations up to 4th with OD off and slowly coming to a stop allowing it to shift down by itself as much as possible. I have no idea if that is true, it sounds logical, and at this point I am just trying to keep this old girl alive. She has taken a beating through the years and never let me down. I know it's time for something new, I'm hoping to keep her going till fall or longer.