As far as leasing and new vehicle warranty, thats nice that someone else takes care of it, but vehicles never break down when the dealer service department is open, they wait until a weekend or holiday and then you have to have it towed to the dealer, find a rental (paid for by them or not its still a pain to transfer everything over), etc. To me thats like saying you know a storm is coming but your going to wait for FEMA to take care of you. I've had a couple broken parts on my non warranty vehicle, one was a fuse, simple enough to replace after I had overlooked it the first time and pulled and replaced the starter, other was a flat tire which I fixed with a plug kit and since I have a full size spare was able to drive the 250 mile trip home easily.
Keep your older one and keep maintaining it. Any small parts you can always buy extra. Find out why your transmission is failing multiple times, maybe its running hot, add a gauge and see then add an external cooler.
Now is a really bad time to buy a new vehicle, the price of fuel keeps going up and many more hybrid/eectric/alternate fuel vehicles are in the works so your better off waiting and see what ends up being our fuel source in the long run.