MAKE SURE YOU HAVE ICLOUD WHEN DOING THIS!
Step 1) Delete the Asphalt 8
Step 2) Redownload Asphalt 8
Step 3) When you enter Asphalt 8, it will ask if you want to continue on ICloud, click Yes.
Step 4) Go to play and it will reward you with 40K credits
Step 5) You can wait a few minutes to delete the app and do this Process again, but to do it again Immediately, play a multiplayer match so your credits save!
You could do this glitch multiple times so it is a Rinse and Repeat thing. Tell your friends before this gets patched and I have never seen anyone do this glitch before so please subscribe!