Only aftermarket stem and boot seal kits are available since Whirlpool discontinued them a couple of years back and, unfortunately, the quality isn't anywhere near the originals. Just keep that in mind.
The tub bearing is still available from Whirlpool (Whirlpool bought out Maytag in 2006) and the same high quality product from yesteryear. Here's an NOS one from Ebay for a good price.
https://www.ebay.com/itm/177476973621
You won't see water leaks until the seal totally fails, it can very slowly seep into the agitator shaft and tub bearing areas for many years without leaking one drop externally.
Keep in mind that adding gear oil to the brake assembly only lubricates the brake friction material as it's a wet braking design. This has zero effect on the spin cycle. You can remove the radial bearing on top of the brake package and inspect it but it's very rare that this part fails without making a racket, they generally roar like crazy during the failure stage.
This is what a bad radial bearing sounds like when it's on it's way out:
The brake is lubricated without disassembly, you'll see a small 360 degree lip underneath where oil can be added.
Make sure the sliding motor carriage tracks are clean, well lubricated, and the assembly glides very smoothly forward and backwards. Make sure the both motor carriage springs are present. All pulleys (motor, transmission, pump) are clean with zero traces of oil or belt material. Use brake clean and a paper towel. Keep cleaning until the paper towel shows zero contamination.
It's worth checking the pump bearing by removing the belt and slowly spinning the pump pulley. It should spin smooth and easily without any rough spots. Check the belt tension of the pump by pinching the belt in the middle and slowly squeezing until the motor carriage deflects with the machine on the ground. The distance between the belt should be on the loose side of 1/4 inch distance. The tighter the pump belt is adjusted, the looser the transmission belt becomes. For this reason, it's best to be slightly on the looser side of the pump belt adjustment than too tight.