I have a 2004 silverado Z71 with 5.3 engine and recently noticed a few drops on fluid on my driveway. I crawled under to find some transmission fluid sprayed all above my transfer case. It appears to be coming out of the vent tube. I started having my service 4wd message appear on my dash a few weeks ago. My transmission fluid level is where it should be so I think this is a small leak right now. Does anyone know what can cause this? My 4wd drive works fine other than when that message appears then it won't work until I reset it by turning off the truck and then turn it back on. My transmission is running fine too. I have 225K miles on it. Any help would be appreciated. Thanks.

 

Some old oil seal somewhere has failed.

 

Is this an easy repair? Can you be more specific on maybe what seal has failed possibly.