I still own that Mustang. I bought it off my dad when I was in the Navy. He bought it in 1987 when I was twelve years old. He just turned 40 and this was his first new car (also, it was his first Ford). The thing is a stick but the 3.27's would have worked well with the turbo, the thing had no traction below 60mph. I don't remember what the autos came with back then. I still have the car and want to redo it someday.

Like MSCA pointed out, not much risk if installed correctly. However, the stock differential works off a dynamic viscous fluid principle. Great on paper, sucks in practice. You're best off searching some of the G35 and 350Z forums for more infomation on this because this differential has been around for a while. If you are serious about wanting to get off the line quicker then gears are a step in the right direction, but in my opinion changing to a reliable differential unit is a must. Problem there is, the price for these diffs. for these cars is stupid expensive. I was not happy paying $500 for my Detroit Truetrac and that's half of what these even start out as.

 

Only specialized/experienced can perform ring gear installation. Sure it is simple and straight forward until you have to take it out, buy new part and start over again. However swapping out the whole unit is an easy job anyone can do it in their drive way.
Shorter tires could also give some of the effect of lower gearing.

 

Just trying to find the parts needed.

Mynismo
Z1Auto

Why do they look different? I'm assuming one of the sites, or both, have the wrong pictures.

Also, if I was to get an aftermarket lsd, and would still like to install 4.083 gears, I would still have to purchase the nissan ring / pinion?

 

Is it necessary to get the aftermarket LSD? also I heard we need to get a bearing as well or no?

 

Also is there a manual version and auto versian z1 auto seems to sell one for a manual only

 

My '87 Mustang GT was my first new car too. It was actually the second car I've ever owned. I can tell you this: Back then, all 5-speed 5.0L Mustangs came with either 2.73 or 3.08 gears. My '87 came with the 2.73 rear end. At the time, I never even realized that 3.08 were an option. My second Mustang (LX hatchback) came with the 3.08 rear. That car also had A/C delete and was pretty much completely void of options. For whatever reason, it did have power door locks. Seemed kinda odd, considering it was basically a stripped car with the "performance" axle. I took that car to Englishtown and ran a 13.90 with it when it was 3 days old. It was about 1/2 second faster than my '87 GT. Anyway, those were the only two axle ratios you could get with the 5-speed manual. I'm almost positive the 3.27 gears were standard issue in the AOD 5.0L Mustangs. Most guys with automatics swapped in 3.73s....which seemed to work really well with the automatic transmissions.

I wish I still had my '87. It was a blast to drive, even if it's not considered fast by today's standards. Back then, it was one of the quickest cars on the roads.

 

What about the speedometer? Is it still accurate with the Gear change? Dont you have to change a spedo gear or something?

 

Speedometer and Tachometer are both still accurate when doing this mod.

 

Staples is correct. To expand on that, the shop manual says the vehicle speed signal (wheel speed) comes from the ABS actuator (sensors that are on the hubs).

 

Thanx bro. I was wondering about that cuz i remember on my mustang it was a problem if you didnt change the speedo gear. I think Im going to go with this mod cuz i like the car just the way it is stock but always wished for a little more low end torque. Anyone know what the rpm are at 75mph in 6th gear with 4.08's? I usually dont cruise any faster than that.

 

That isn't right. With stock gear 76 MPH in 6th gear is exactly 3000 RPM. So probably about 10% higher than that or somewhere around 3300 RPM.

 

Sorry, you're right. There's about a 200-250rpm difference between the stock and 4.08s

 

Are you guys who did the 4.08 experiencing any whine ? I had this done in my 370z and as for the performance increase, it is substantial and the car feels like its on steroids now... It def decreased traction but not uncontrollable.. its also 50ish degrees and I am on nt05s so that doesn't help, but I break loose in first almost always and can hit second and have it bounce off rev limiter spinning.. its pretty funny. Driven properly I can completely control traction though..

But before I go back in to the shop to complain about the whine I want to make sure its not normal with OEM 4.08 final drive from the frontier.

I get it at a constant cruising speed pretty loudly, and and other times too, basically any rpm over 3k produces some whine, but its at its worst when cruising at 80 at 3400. Gas mileage will get worse if you done lay off the throttle and cruise at the same RPMs as you used to, thats inevitable since at every speed your rpms are now higher.. slow it down 5 mph and your back to normal gas mileage and your avoiding speeding!

 

Close, it's 9%

3.692 stock divided by 4.08

Stock 3.692 is 48 teeth on the ring and 13 on the pinion.

While 4.08 has 49 teeth on the ring and 12 on the pinion.

 

There should be no noticeable whine with any rear gear ratio change. Sounds to me like the backlash wasn't set properly. I'd go back and complain if I were you. Don't let them BS you by trying to tell you that whine is normal with a ring & pinion change. It's not.