Throw a trans cooler on the 42rle. It's a cheap insurance piece that'll help keep it happy. I've the the Derale cooler that's made specifically for the TJ/LJ. Haven't got to put a temp gauge but that is also a good idea. 42rle run hot from the factory, also you can overfill by .75 qt. You'll want the deepest gears you can get, I'm running 5.38s with 37s, being a little deeper would be ideal but I'm happy with it. At 65 I'm running 2250 roughly. I believe 5.13s are lowest for the 30 up front. As mentioned OD is terrible and the trans tuning from factory is even worse, deep gears will be a great help