I have a 2008 Jeep Wrangler unlimited. It’s been a solid vehicle with minor repairs over the last 27k miles I’ve owned it. I just hit 100k miles and have been hearing it’s pretty common for the 42rle to overheat. I have the max tow package so I’m not sure if I have a tranny cooler or not. I’ve had zero problems (knock on wood) with it. If I don’t have a tranny cooler should I look into getting one?

 

Your 2008 automatic JK has a transmission cooler at the bottom of the AC condenser. It's small, and it's not in the direct path of air through the grill. That's why the early automatic JKs tend to overheat more than the 2012+ JKs. (2012+ JKs have a larger cooler right behind the grill.)
It looks like you have not had a problem with overheating, so there's no hurry to add one. Adding a cooler would still be a good idea, though.

 

Great. Every once in a while it will shift into overdrive kind of rough. I’m not having any of the bad problems that people have been stating. I occasionally tow a small boat but that’s it.

 

What about turning off overdrive altogether? I've been driving this way for the last 60k+ miles and it feels better overall...from take off at the stoplight and power on the highway. If I recall, driving with O/D off tends to reduce heat buildup since you're not into and out of gear so often. Probably time to change out the fluid & filter for some peace of mind.

 

What’s your mpg looking like? Right now I’m getting 16.5 mpg. It’s mostly city driving with speeds up to 55. Whenever I tow my boat I turn o/d off. I think it would make since to do it in the city but I do like it on the highway. Did you notice a huge change in mpg? My fluid looked fine last time I checked it.

 

I get around 16-16.5 mpg with mostly city stop and go, but then again I'm also running heavier weight 10w-30 oil too....so I would say OD off is not much of a factor unless you're doing long stretches of 70+ mph @ 3000+ rpm runs.

 

Gotcha. I’m running 5w20. How many miles do you have?

 

I just made 90,100 miles this morning.

 

Great I’m only 10k ahead of you. What makes me feel better is most people said that they had problems start way before 100k. I’m hoping I can get at least 150k out of this before a rebuild.

 

Mine has 211,000 miles of running with the O/D off when not on the interstate.