Replacing 5th Gear & Synchro Ring on a 04-09 Mazda 3

This video I made shows how to swap the factory .75 ratio 5th gear set on your 04-09 Mazda 3 with a higher .71 ratio set. This will lower engine RPM by about 200 RPM at 65 MPH in 5th gear and should give you a 1-2 MPG increase. There is a higher .68 gear set but it was only available on Mazda’s equipped with a diesel engine that weren’t sold in the states. I also replaced the 5th gear synchronizer ring since it would sometimes grind. This swap is only for vehicles with manual transmissions. You can buy the .71 gear set online: You can also source it from a vehicle in the junkyard. 97-02 Ford Escort sedans and wagons have this gear and are pretty easy to find. This is how you remove the gear set from the Escort: #post-734651 You can also get the gears from other Mazda’s like the 626 v6, MX6, and possibly the Ford Probe. I’m not sure of the details t