The timing belt in these vehicles are the only weak point I know of-I haven't heard of that many problems with the cooling system other than the rads going out and in most cases the driver has enough sense to pull over before any real damage occurs-it's different with BMW's their cooling system can go out and your looking for a new head right away.
On your timing belt-if you want to be sure about evrything I would if it were mine replace the belt along with all the pullies and tensioner just to be on the safe side-not that hard to do-Dewfpo has a good write up that got me through the first and the secound time was a peice of cake.
I would change the water pump and serpentine belt at the same time.
On the tranny side-I flushed my tranny in my driveway using the write up thats found in the Faqs-what a diff that made-you could hardly tell the tranny was changing gears ,it made it so smooth-I added about 6 ozs of Auto R-X to the tranny and drove her about 3oo miles or so before doing the job.
With syn oil I change that out at 7k miles now with a new filter added every 3500 and then top off the oil afterwards.
Hope that helps
Poolman