Help Any way to change to 4G while sleeping?

[roller6902]

I'm trying to find a way to be able to switch to 4G (or even 3G if I can) when my phone goes asleep.
I obviously don't need 4G LTE when it's sleeping, since it will run my battery life rather quickly (plus fumble to try and find an LTE signal at times).
I'm just wondering if there is something (non-root or root) that will let me switch to 4g/3g after I put my phone asleep.

(and to be frank, there hasn't been that much of a drain, but 2% per hour can irk me a bit)

 

[DMedina559]

I suggest juice defender from play store, it has an option to turn off data when phones screen is off

 

[roller6902]

I suggest juice defender from play store, it has an option to turn off data when phones screen is off

The thing is, however, I don't want my data to turn off, I simply want it to switch from 4G LTE to 4G/3G when I put my phone to sleep.