After searching, I understand that the manual G37, 370Z, and late G35 all had 3.7 ratio gears in a case that bolts directly into the 350Z. For some G35 diffs the pinion flange must be swapped to attach to the driveshaft. Some of these were LSD as well. The gear ratio change is a nice upgrade over the factory 3.3 or 3.5 ratio. I'm interested in this option because there is no disassembly or re-shimming involved, unlike a normal gear or carrier swap. My question is where can I find these differentials for sale? Do any vendors sell them?

 

http://car-part.com/

 

I have a base 08 and I wanted the lsd with shorter gears as well. I found a full diff on eBay from a 370z with the limited slip and it bolted right up no problem..speedo reads about 5mph faster than I'm actually going but other than that all has been well

 

08andawesome that is exactly what I'd like to do. My car is a DE so it won't benefit as much as your car, but it will definitely accelerate more quickly. I'm just having a lot of trouble finding one for sale. Many places have the 3.3 and 3.5 ratio differentials, but the 3.7 ratio ones seem to be rare.

 

Why is your speedometer off? Aren't you using your original/OEM sensors?

 

I am currently upgrading my diff as well. I have been dead set on getting 3.7, but after researching prices it's cheaper to get the 3.9. I was searching for 370/G37 diffs, but they're too expensive right now and too few.

Plans are 3.9 gears, nismo finned cover, full bearing swap, and stiffer diff bushings. Z1 has a great rebuild kit, but I was able to piece together the same parts through a few websites for about $150 cheaper.

 

To get the 3.9, you need to find the rare diff that came in some G37S's or buy the ring & pinion aftermarket and install them with a shim kit. Both of those are too much hassle for me, so I'll settle for the 3.7 gear. I really like the SPL aluminum bushings in my car, but they add a little interior gear whine versus poly diff bushings.

 

^ i have a 3.9 vlsd diff for sale in the marketplace

 

Bmurray, thanks for the info. I actually saw your diff and headers on ebay.