The '89 has the single cam M103 engine which does not exhibit the head gasket oil leak as does the twin cam M104 engine.

The upper timing cover is, however, a common source of an oil leak. If so, you will see oil at the corner of the head/block/upper timing cover. It is usually a seeping leak, not a "pee on your driveway" leak.

If this is where you find the leak, it can be fixed relatively easily, but you need to use the correct sealant on the U seal at the bottom of the upper timing cover. The correct sealant is slick enough to allow you to push the cover rearward to put the shaft seal in place without disturbing the location of the U seal.

As far as the transmission leaking, I would be surprised if this automatic is any more prone to leaking than any other. The only way I know how to prevent having an automatic transmission that leaks is to buy cars with a manual transmission.

Good luck,