Lightly tap the cover a few times if you think it's in a bind. From my experience, get the longest pry bar you can fit under there to apply pressure to the cover. The more leverage you have, the easier it's gonna be. While the cover is pressed in, use a pick and pull out the retaining ring. After you get that out, gran the o-ring that's on the cover and pull it out to where you can grab it with your finger then cut it and pull it out. The cover should pull off pretty easy after that.
2005 AWD Silverado SS-CAI, Shorties, X pipe, SLP Loudmouth II, HD2 Shift kit, Corvette servo, tru-cool 40k, Yank SS3600, 160 Stat, Nelson tune.