Rear Diff Oil - Change to Synthetic

[Diesel1]

Does anyone know what weight gear lube is reco'd for the rear diff? Unfortunately I'm at work and don't have the manual in front of me.

I am thinking of switching to synthetic and just want to make sure I buy the right oil. From what I read, Royal Purple/Mobil 1/ & AMSOIL lead the pack. Has nayone changed their rear diff oil to synthetic and if so, any impressions/feedback? At the very least, I would hope to pick up a little better fuel economy, but I am not expecting much other then better protection.

Thanks!

[Brando]

You have prob found the specs by now........but,

I had mine changed out with Red Line Synth at around 16K miles.....and there were some small metallic shavings visible in the old lube.....from normal break in.

[Diesel1]

Thanks Terry! I am gonna have to flip through the manual tonight...before we get another 3-5" of the fluffy white stuff! URGH!! I can't believe I am actually looking forward to seeing pollen on my car instead of snow!

[OATKE577]

I was reading an article in the Hot Rod magazine (I think that one) a couple of years ago or so where they switched the engine, tranny and rear differential oils out with Royal Purple synthetic all around. They were able to pick up 10 hp to the wheels.

Just thought I'd share, I'm only at 1k miles on my G but I'm leaning towards dropping synthetic in when I go in for my first service.

Whether or not it gives that kind of performance on the G is another but every little bit helps, right?