John, check with your GM dealer.  On my 04 Suburban I got a notice that GM was extending my instrument cluster warranty to 7 years or 70,000 miles because "your vehicle could develop a condition where one or more of the instrument panel gauge needles may stick, flutter, or become inoperative.  This may cause inaccurate readings, including the speedometer and the fuel gauge."

Sorry it took so long to respond, but yesterday I got my new inspection and registration stickers and ran across my notice in the glove box.  I have no idea if this applies to your truck although it sounds very similar.