Why does my engine do that?

Could be low transmission fluid or fluid pressure clogged transmission filter internal damage etc.Do you have any codes in the computer?

Nope not that I remember I'm going tomorrow to garage need new cadillac converter, I will check my tramission fluid do I need the car running for bit to check that? N other problem is everytime inturn it makes a loud rubbing sound kinda sounds like I'm driving a electric car I think it's my power steering but i can't find it. Was told it's hard to put fluid in it cuz it's in a hard spot

Which engine do you have?If there is no visable transmission fluid leaks the fluid is probably full.Check your power steering fluid level see if its low could explain the noise heard when turning.

I have v6 3.8l n yes I will check once I find it. I just don't understand why engine jerks like that like the whole car jerks.

From the sudden viloent engagement into drive is causing it.

How do I fix that problem?

so any codes in the computer?ANy transmission leaks?

Nope

I would check the transission fluid level then do a pressure test.