Need help from some xbox gurus

ThanKs semi pro,but something wierd happened today, I accidentally switched what I though was the good drive into my old 360 but it turns out it was the old one. The only thing I did was clean and re lube it and now it works fine! No stuttering,no wierd laser noises nothing,it works now, WTF? I still plan on flashing the new drive as I'm
sure this one won't last long and I thank you guys for the explanation on flashing, but until then I'm happy I can finally play again! LOL!--Josh