When I start up and shift into reverse I hear a slight grinding sound. It doesn't sound like it's coming from the transmission though. I hear it in the rear behind the drive shaft and randomly from the front. It sounds like metal on metal.

For the rear I'm thinking that maybe I need to change out the rear diff fluid. If this is the case, then is the plug easy to reach?

For the front, I'm at a loss. It seems to only make this sound when it's a cold startup too.

As always you guys are great and any help is appreciated.