Originally Posted by Raydee35
Hope this helps:
Originally Posted by bullswife98
[How To] Enable 3G only mode
As some of you may have noticed there is no choice in the network settings for 3G only. But actually there is. Here is how to do it....
1. Open the dialer and type *#*#4636#*#*
2. A menu will appear – choose “Phone information.”
3. Scroll down until you see the pulldown menu for “LTE/CDMA/EvDo/etc.”
4. Tap on that menu and choose “CDMA Auto (PRL).”
4. Hit the back button to get out of these menus and to your home screen.
5. Wait 20-30 seconds and watch your 4G LTE logo turn to 3G.
6. To confirm you are on 3G only, head into System Settings and tap on the “More…” button.
7. Tap “Mobile Networks” and “Network type and strength” to see something like this: