Ok, first off, I know I have posted this in my Gen3 section, but since it's about as active as bad yeast, I am gonna ask this here.

I am changing all my fluids over to fully synthetic hopefully this upcoming week.

What should I expect for power(anything?) mpg differences?

I already have the rear diff. and motor oil fully synth.

And lastly, I have a manual transmission, will I need to do a "flush" of the transmission fluids? Or just drop the transmission pan and change it out that way? What's up, I've only driven automatic vehicles before, and this has me in a "boggle" to say the least.

 

I could be wrong but your differential probably came with syn in it.

As for gains, there has been several HP TV shows that replace all fluids with syns, Royal Purple, M1, ect. Of course they have all the cool toys and can do base and after dynos. Usually it yields about 5 RWHP, which means you will not feel anything.

 

What about like mileage or anything, or does it not get affected that much by this?

 

The only thing I have ever noticed with synthetic is less wear on some parts when I've torn into an engine. Although I would swear up and down that my hemi feels like it revs faster than it would with non-synth oil.