I wouldn't worry about it till at least 50K unless you are tracking the car.

 

sorry to resurrect and thread-jack
I took my 2008 G37S in for warranty work (valve control issue draining the battery). The dealer performed an inspection and found that my transmission and differential oil needed to be changed, as well as my cabin air filter. I can change the cabin filter (using the sticky here - https://www.myg37.com/forums/d-i-y-i...ent-video.html), but I'll need help on the other two.

What are some recommendations for transmission and differential oil brands?
Any DIY guides, or would you recommend me taking it to shop?

I've been lazy in changing my own engine oil, so I just pick up the oil and filter, then pay the $10 to my local shop for labor. If it's easy enough, I'd be willing to give the other oils a try. I just hit 50K miles btw.

 

Trans fluid, diff fluid gets very dirty after the 1st 15k miles. This is because parts are new and a lot of metal shaving floating around. I saw a trans flush coupon for $150 from my local dealer. Diff fluid is easy to inspect and change at home.