Hi,
What model do you have? If you have a model between 2002-2004(5) the Mopar transmission Skid plate available won't fit directly, all other Skid plates Mopar will bolt on without a problem (might need to drill the odd extra hole to secure them proparly.
My self I have a 2003 CRD and have fitted all Mopar Skid plates from the front to the Tank, but the transmission Skid plate gave me a lot of trouble. Saddly the skid plate for a 2002-4 model is no longer available for sale, but you can only buy a 2005-7 from Mopar and it doesn't fit correctly or securely. I had to modify it, had extra steel plates welded on and need to make an extra hole on the front cross bar to secure it.
Modified one where I added 2 (40cm x10 cm x3mm) sheet of steel welden on so that I could bolt it correctly (the picture on the right is how it looks originally for a 2005-7 KJ, I had them power coated for protection) You can also see where you need to drill an extra hole at the back of the skid plate so that you can bolt it one to the rear cross member as the original holes will not line up.
You can also see my post here ( I need to up dated it) viewtopic.php?f=3&t=54621
Hope this helps.
Fil.