Need new rear axle and differential 2500HD GMC***UPDATE***

Thanks. I did take it to the dealer for service. In fact it was scheduled to go in the following week for a recall on the axle nut. Something like checking the torque on the rear axle nut. I called and told him about the fluid and he said to bring it in right away and they would take a look at it. Glad I did. They said the failure wasn’t related to the recall.