Making noises how to fix it?

My car jerks whenever it is moving from gear 2 to 3. Once it gets to 3, its stable till4. The moment i slow down to gear 1 again, it happens every time

When i turn off car engine makes a squealing noise, only when turning off car

The oil is leaking into the cover gasket seemingly from air pressure under it so the car plugs are dranched in oil cause low power of 1st gear clutch control and others, when driving it makes a lot of… 

Gear oil pressure to low faul

Engine getting pressure and some noise