Reading about this warranty issue really burns me up. I had a ZJ that was plagued with tranny issues. Chrysler avoided replacing it at every cost and just patched the problem. The tranny went through 3 major repairs when it was owned by my aunt. The tranny eventually blew up and left her stranded on the highway. The local dealership said they would not cover the replacement of the trans, even though it was still under the warranty period. A letter to the president of Chrysler Canada is what it took to get the trans replaced. Now I'm not too sure what the exact problem was, but the trans whined loudly and shifted hard. This issue started at just under 3000km! The trans was replaced when I bought it, but I still had problems with it. Like when the CPU went and there were none available in North America....?
FWIW: If I were you, I would go to one of those Chrysler dealerships in town that have brand new vehicles (preferably a Jeep) which have aftermarket lifts on them and act as a potential buying customer. I would ask what the warranty coverage is on the vehicle now that the height has been modified with a lift and tires. I would find out as much as I can from someone at the dealership that is in a position to know, not assume, like the service manager. Ask if you could get something in writing verifying how the drivetrain warranty is affected by the fact that vehicle has been lifted and sold to you as a brand new vehicle.
I'd then write a letter to the head office of Chrysler Canada. Keep it factual and ask for a response as to why your major drivetrain component has been declined warranty coverage under the prescribed period. Ask them for answers as to why they are selling modified vehicles if they aren't going to offer the same warranty coverage on them. Explain your situation, soon be 4th year trade, looking at a diesel pick up and tell them that this issue has deterred you from buying a Chrysler product. (providing you didn't buy a Dodge diesel!) I would also include that you are in a Jeep club. I would ask that your be issue be resolved and the replace the T-case. If you are not happy with the initial response, resend it to someone higher up. I would keep on them, rattle their chains at the head office level.
To me, this is a matter or principal, not money. Isn't this the same company which is going to offer "lifetime" drivetrain coverage on selected new vehicles?