Oil pressure/transmission noises
I've got a 98 XJ 4.0. Runs and drives absolutely beautifully, with the exception of a few problems.
First, the oil pressure gauge is kind of wonky. If I hard accelerate to pass a vehicle, the gauge will actually go backwards toward 10-15 PSI and then back to 40 after I let off the gas. Sometimes, the gauge will always read at 40-50, or just slightly below 40 depending on idle speed.
I just replaced the sending unit in January. Possibly a defective one? It's from Auto Zone or Advance (Can't remember).
Also, and this has been this way for as long as I have owned it, on downshift when slowing down, there sometimes is a noticeable CLUNK when the Jeep shifts into 1st gear. Sometimes, it clunks the same way when taking off from a stop light or stop sign.
Aside from that, it's a super truck and couldn't be happier with it.