2001 Rear Leaking.

Hey guys,
I have an 01 Silverado Ext. Cab and just noticed my rear is leaking.
I bought the truck brand new off the lost and I don't even have 20,000 miles on it yet.

I have a warranty, 10 years or 100,000 which ever comes first.

I want to bring it sometime next week, is this covered by my warranty?
One last thing I just dropped it by a 2/4 Belltech kit about a month ago, will this be a problem with the warranty as well?

Just give me some advice on heads up.

rear? im not a big truck guy but im assuming your saying rear diff. anyhoo on mine i just a packed some silicon sealer around the cover - ghetto fabulous but it kept me from having to take the cover off agian and its working.