3000Gt cracked transaxle?/ shift lever seal

I have 91 3000GTSL 80k mint cond. I found leaking gear oil coming from a few hairline cracks in between the casting ribs right around the left axle output of the tranaxle! This car as never been beat on, ever....when to the dealer they want
2k for new trans! has anyone ever heard fo this happing before?

Also the seal around the shift lever whereit goes into the trans is bad and needs to be replaced. How do you get the shift lever out of the trans? I tried everything with
no luck.......