I have a 1999 CHevy blazer and when ever you drive you hear a constant clunking. Sounds like from the axles in front. The 4wd went in august and was stuck in constant 4wd so we took out the axle. Was wondering if the front differential might just need fluid (if so does anyone know where the fill plug is). If it is the axles was wondering if I could just take them out in the front because 4wd will more than likely never be fixed. Any help people can give would greatly be appreciated. It does not sound like the bearing either.

 

Lift the hood up and inspect the hood hinges. Wiggle the hood, the hinges may be loose. There is a TSB on them. Many think it wa the drivetrain, but hopefully it will be a simple fix.