8320 shuts off during calls!

Ok, I've had this problem for a almost two months now!
While I'm on a call I start hearing some noise... like when you're speaking on a mic and you have your cellphone pretty close to it (if that makes sense)... after about 5-10 seconds the phone stops working and I can't get it on until I pull out the battery. It happened a couple of times while I wasn't on a call.
I was suggested by some of you to get a new battery and so I did. It's been a lot better, but it still happens! :confused:
I have upgraded and downgraded my phone to all the 4.5.x versions that I know of thinking that it was a problem with the OS (it started happening when I upgraded to .124, prior to that it was pretty stable).
This last time I downgraded to 4.5.0.52. I didn't restore any applications or settings (only address book & calendars) just to keep it as clean as I could. No third-party applications are installed either... but the problem is still happening!!!
When I have my phone charging and I'm using a bluetooth headset I can talk on the phone for hours (literally) and it will work just fine...
Could it be a problem of compatibility between Tmobile and my phone('s OS)?

Any suggestions? PLEASE! :o

I doubt its the OS, but it could be a possibility. Also another possibility is a bad sim card.

I have another sim card that I could try... but I doubt it's the sim card just because I often listen to the music stored on the card and never get an error or anything... but I can try!
Any other suggestions?

Id try reloading the OS, then the SIM, if none of that works, Id call tmobile as it may just be a plain ol hardware issue.

Go to Options >Status, tell us what your free file is...

@rachel0179
I've reloaded the OS a few times... I'll try the SIM... I bought my BB on eBay so I don't know if tMobile would do anything

@SevereDeceit
File Free: 20732376 Bytes

contact the individual you bought it from and find out the history. might not get a response if they know they sold you a device they knew was jacked.
physically go to tmo and they will give you a fresh new SIM card. its worth a try. I go through a sim per yr.

I changed the memory card, I even formatted it on my BB... I have a clean install with no third-party applications and the problem is still happening... is it my phone?

@ndnoutlaw:
Do I just ask for a new sim? Will I be able to keep my number?
How could it be the sim? (just curious)

Did this issue ever get solved? I am having the same issue!:mad:

if i was you, i will call your carrier and get a new phone

It could also be a battery that is going bad. It may look like it has an adequate charge, but if one or more cells in the battery are bad, then it can't keep up with the current demands of the radio transmitter, so it shuts down/reboots.

Easiest way to test it is to plug it into a charger and make some extended calls. If it is the battery, it will not reboot/shutdown while on the charger, because the charger is supplying additional power.