My 2006 Z just turned 33K miles. Did all the basic stuff like oil/filters/coolant changes. However, Sch 1 and Sch 2 chart didnt mention anything about rear diff and manual transmission fluid changes. Are these required maintenance items? How about brake fluid changes? Cant find anything about it either. I dont race my Z and I drive like the old man I am. Input please!!!

 

You are correct, they don't specify a particular interval. Basically it's an "inspect and replace as needed" condition. If your fluid smells burned, is too dark, etc. then it would be a good time to replace it. At a minimum, you'd want to replace them at 50-60K miles, just because of the age of the OEM fluids. Go with synthetics in both the diff and tranny. You'll see a bump in MPG.

 

Dave, just out of curiosity, how big a bump in MPG by going to synthetics in the diff and tranny? I noticed a significantly smoother shift in my last car (Mitsubishi Eclipse 5sp) after changing out the MTF with Amsoil Synthetic, but it did nothing to my MPG (I'm guessing that's because the fwd diff on the Eclipse wasn't affected the way it would be in the big rear diff housing we have on the Z). Thanks.

 

When I went from 18" OEM wheels and tires to my current 19" setup, I saw a drop of about 3 MPG on the highway. Shortly after that I changed from the OEM trans and diff fluids to Royal Purple and saw the mileage go back up a little over 2 MPG.

There's a lot of stories about how the shifting changed after changing the trans fluid. Unfortunately, in my case, the shifting got worse with RP. After a few years, I changed to Redline and didn't notice a great improvement either. Maybe next time I'll try something else.

 

Hmmm.... interesting. Thanks. I may try the Amsoil again. My MPG is pretty dismal and I'm willing to try anything short of a Kia motor swap to up the numbers a bit. I'm going to be throwing on some Continental low-rolling resistance tires in a few weeks, which reviewers claim about a 5-10% mileage improvement on, so we'll see how that goes. I only got 15,500 miles out of my factory Potenzas, so anything's got to be an improvement from there.

 

Tire life seems to be a big function of alignment. I've been getting over 20K miles on my PS2s which I feel is supurb. I no long run the OEM alignment specs though.

As evidenced by my drop in mileage when going to bigger tires, the rolling resistance is a killer. I wish tire manufacturers had to publish some kind of standard measurement of rolling resistance. It would make picking a tire a lot easier.