Can I get my phone replaced after a 3rd party repair?

Hello thanks for reading! I have a Sprint Galaxy S4 that has been experiencing shut down problems for a while, (shuts down randomly or when set down lightly) and wanted to get it replaced under my warranty. Unfortunately, yesterday I cracked my glass. Disallowing me to send it in for diagnostics. I was wondering if I could replace the glass myself without Sprint noticing my self repair. Can I get away with it?

And if not, can I fix the shutdown problem myself?