Why is my LG-G2 now always running hot and slow after switching SIM from Verizon to T-Mobile?

[AC Question]

I recently switched my unlocked SIM on my LG-G2 from Verizon to TMobile. The SIM card worked fine but now I'm noticing that my phone is constantly running hot and most of the time I'm getting 4G speed rather than LTE. Yesterday, I couldnt even update and/or install a single app. At best I was getting upto 80% complete before it would freeze. I stopped in a T-Mobile store and naturally I was told I needed to purchase a t-mobile device. Yeah right...pee on my back and tell me its raining (lol)!! I admit I'm a newbie to all this tech stuff but from what I've read, it's possible to match this switch and still be able to use my current phone without issues. Can anyone assist? PS...Please be gentle with the verbiage when you reply because 9 time out 10, I will have no idea about what you're referring to when speaking in 'tech' language.

~Thanks in advance

 

[Rukbat]

It was running the CDMA radio on Verizon. It's now running the GSM radio on TMobile. Either the GSM radio just runs hotter or there's something wrong with your GSM radio. (The two radios are different. It's like running a radio, then switching to a TV - totally different electronics.)

 

[BigLes86]

Thanks for the reply Rukbat. So how do I find out if there's something wrong with the radio, and if so, is there a potential fix? FYI...I seriously doubt there's a problem with the radio because my wife has the same phone which we both switched from verizon to t-mobile on the same day and hers is doing the same thing. Just need to know the best resolution to all this. Thanks again!

 

[Rukbat]

It depends on what you consider hot. 60C? Much too hot for any electronic device. 45C? Warm, but okay.

Run LTE Discovery and see how bad the Verizon signal is where you are. If it's weak (higher negative number, -70 is pretty strong, -120 is useless), the phone assumes its signal back to the tower is going to be weak, so it keeps the transmitter at full power, getting the phone hotter and using more battery. The solution, in that case, is to get a carrier with a better signal where you need service.