hi guys, I'm sure this has been covered, but I couldnt get a search to give me what I was looking for. How many of you are running synthetics in your diff/rear end/ transfer case etc..? any increase in smoothness or MPG? I've heard its not the best in synchromesh trannys, but what about the others? I may stick with dyno in the engine, its been running on it since day one, and is very smooth. Plus at $12 a gallon for castrol right now its hard not too.!