Having the main seal blow is rare. It only happened to me because I was running a thicker oil and was pushing it hard on a cold day. Not likely you'll ever have this happen to you. Here's a few threads for your review regarding transmission shifting issues:

http://www.toyotavantech.com/forum/s...months-sitting

https://www.toyotavantech.com/forum/...ble-adjustment

https://www.toyotavantech.com/forum/...erdrive-issues