If you are reading this page you are probably having problems with your 4 speed automatic transmission. The 42RLE transmission is known to be problematic. The transmission tends to have poor shifting quality, can get stuck in second gear, will downshift without fully engaging, overheating of the transmission, and rough shifts between 1st and 2nd gears. To make it even more complex it is computer controlled and the torque converter engages too early which contributes to poor shift timing.

Unlike many other Jeeps, this isn't a part that you can easily just swap out for a better one. There are too many variables. Mostly being that this transmission is integrated into your Jeep computer more than other easily swappable transmissions. There are definitely other transmissions you can replace this with but it would likely not be cost effective. The best solution is to merely fix the 42RLE and do a couple things to help prevent any issues in the future.

Here are a few things you can do:

  • Turn off overdrive using the dashboard switch.
  • Make sure your gearing is sufficient to run your tires.
  • Install an after-market transmission cooler

UPDATE:
There is an upgrade for the 42RLE from Mopar. You can upgrade the transmission pan for the 2003-2006 models. It upgrades the design of the pan and increases the capacity. It also uses a different magnet which is supposedly better too.

Here is the part number info for the parts:(should cost less than $50 for everything)

  • Pan: 52852912AC
  • Magnet: 4446728
  • Filter: 5282913AB