More T-Series transmissions

Hello! I was recently playing this lovely game and realized that I don't feel like setting up my g27 shifter for the twelve gears that the T series has. How could I make it six gears, or better yet, an automatic? I would like to create a mod for this, but I don't know how. Thanks!

 

I will if u want

 

Please do! I would love it!

 

Here u go

 

Thank you.