4.08 Gear Install (7AT) Review

dthem370

Hey Guys, when I was doing research on getting 4.08s for the 7AT 370Z I noticed there was a lot of people asking questions that were not getting answered. I'm going to give you guys some information I read up on and also my review after getting my gears installed yesterday.

Informational:

-The 7AT will lose cruise control. The light will just flash when you try turning it on.

-The RPM increase is around 600-700. See Videos of before and after posted below.

-Due to the RPM increase, there will be a decrease in highway MPG, but you can possible see an increase in MPG in city driving since it takes less work for the engine to get to the speed limit. Personally, I didn't notice a difference at all.

-For the 7AT you will need the differential from a manual 370Z to install the 4.08s.

-You can use the stock VLSD or an aftermarket one.

-The top speed will decrease from something like 200MPH to 180MPH. Realistically I doubt any of us will ever go that fast.

-Acceleration increases throughout all the gears and you will notice a loss in traction especially in 1st gear. Throw some good tires on there and you should be fine.

-Down Shift Rev Matching seems to be unaffected and seems to be working fine. I will drive it more in sport more within the next couple days and update if I notice anything different.

-The car is much more fun to drive now!!!

My Review:

I first want to start out by thanking Seb at SpecialtyZ for doing my install. He always does great work and answers all my questions. This is the only place I trust to take my Z. This time he did the gear install and GTM transmission cooler for me. Everything so far is working flawlessly!!!

After driving the car, you will instantly feel the difference. The car feels much faster and torquier. First gear is really short and 2nd and 3rd gear feel like your in a rocket. The fun factor is really where it's all at. The car accelerates so much faster throughout the entire RPM range, that its just a blast to smash the pedal and go.

Parts installed:
1. 4.08 gears
2. Gear install kit (Seals, bearings, shims, crush collar, etc)
3. Redline gear oil
4. Manual differential w/ stock VLSD

Seb swapped out the 3.69s from the manual diff and installed the 4.08s. Then swapped out my entire stock differential with the manual one.

Stock Gears 70MPH


Stock Gears 80MPH


4.08 Gears 70MPH


4.08 Gears 80MPH