turbobrick
WKR
Monster has a pretty spotty reputation in the performance aftermarket, I wouldn't be buying from them. Looks like yours should be a 6L90E, I wouldn't hesitate to pick up a reman from a reputable source like Jasper or from GM directly. You might be surprised how affordable a reman from GM and having them install it can be. Buying from GM also gives you a warranty at any GM dealer nationwide should there be a problem down the road.