HOW TO TURN OFF 4G IN ANDROID??

Change the settings of your phone to connect only to the CDMA network and stop it from searching for 4G networks.



Many new Verizon Android phones are 4G compatible phones but, as of the publishing of this article, 4G service is only available in a select number of cities. When there is no 4G service, these phones roll back to using the available 3G network. While this can work well, it does create two problems:
1.It drains your batteries as the phone searches to connect to a 4G service. Most smartphone users have experienced an increased battery drain when their phone is in an area with no or limited network coverage, because the phone still automatically scans for a 4G network to connect to. This still applies to 4G phones that are connected to a 3G network. This auto-searching is a consistent battery drain.
2.It sometimes causes problems sustaining your network connection. There are a few known issues with Verizon 4G compatible phones that are connected to 3G networks. Here's an article that describes a quick fix solution,  but the issue continues to adversely effect numerous Verizon 4G capable phone owners.
Fortunately, there are two methods to control whether or not your phone searches for an available 4G network. Turning off the auto-search function will increase battery life and may eliminate several of the network connectivity issues.
Method One (Verizon)

1.Open your phone dialer and dial "##778# then hit your "Send or Call" button.
2.A pop up will appear that will give you two choices: "Edit Mode or View Mode." Choose "Edit Mode."
3.Once you choose the "Edit Mode," you will be prompted for a password to continue. Enter "000000" for the password.
4.Scroll down to "Modem Settings" and select "Rev A" from the options listed.
5.Then change the setting from eHRPD to "Enable."
6.Hit "OK" to save your edits.
7.Press your phone's Menu button and click on "Commit Modifications."
8.Your phone will reboot and will no longer auto-search for any available 4G networks.
When Verizon rolls out 4G service in your area, follow the same steps but choose "LTE" from the Modem Settings.
Method Two
The developers at Cunning Logic have developed and released an app that is available for no cost in the Android Market. Connect to the market and search for their LTE onoff application. 
Once installed, this app gives you the ability to easily and quickly select whether or not your phone searches for any available 4G networks