Alright, thanks for the info. I've had my car about a year but have only put 5K miles on it so I'm not sure Installation Kit 2 would be necessary but I could get it if it makes a big difference.

Rear differential part numbers
 

JUL 08 - Future? - Frontier w/QR25DE king cab
Final drive model: C200
Final drive ratio gear sets:
M/T w/15" wheels = 4.083 = part number 38100-0C760
M/T w/16" wheels = 4.363 = part number 38100-0C860
A/T w/15" wheels = 3.692 = part number 38100-0F56A
A/T w/16" wheels = 3.916 = part number 38100-0B66A

The gear sets will cost you ~$500 from a discount dealer.
The front/rear pinion bearings and companion flange are the same
between the Frontier/350Z/370Z.


R200/R200V
The whole rear differential part numbers:
350Z, manual trans, non LSD: 38301-0C422 (JUN 02 - AUG 08)
LSD: 38301-2C422 (JUN 02 - AUG 08)
Early LSD models (pre AUG 05) had
the same part numbers for both flanges,
38220-AR010.

350Z, manual trans, w/LSD internal rear differential part numbers:
------------------------------------------------------------------
38220-AR010 flange assy, right side
38220-AR011 flange assy, left side
38342-P9010 x2 seal-oil, diff side
38440-0C000 x2 bearing, diff side
38453-N31__ x2 shim-adjust, side bearing (variable part number, won't know until builder inspects)
38420-2C500 entire viscous assy (crap, recomend clutch type locker)
38100-0F46A gear set-final drive (3.538; see Frontier gear sets to upgrade to)
38154-0C0__ washer-adjust, drive pinion (variable part number, won't know until builder inspects)
38120-EC000 bearing-drive pinion, rear
38165-0C020 spacer-housing
38140-0C000 bearing-drive pinion, front
38189-P0117 seal-oil, drive pinion
38210-0C020 flange assy, companion (JUN 02 to JUL 04)
38210-EC020 flange assy, companion (JUL 04 to AUG 08)
43262-01P10 nut-drive pinion (JUN 02 to OCT 06)
43262-01P1A nut-drive pinion (NOV 06 to AUG 08)
38351-0C000 cover rear, final dr (upgrade to Nismo finned LSD rear cover for $50 more; 38351-350DK)
------------------------------------------------------------------
38220-AR000 flange assy, non LSD both sides



The whole rear differential part numbers:
370Z, manual trans, non LSD: 38301-EG53D (OCT 08 - AUG 14?)
LSD: 38301-EH52D (OCT 08 - AUG 14?)
370Z, manual trans, w/LSD internal rear differential part numbers:
------------------------------------------------------------------
38220-JK01A flange assy, right side
38220-JK01B flange assy, left side
38342-P9010 x2 seal-oil, diff side
38440-0C000 x2 bearing, diff side
38453-N31__ x2 shim-adjust, side bearing (variable part number, won't know until builder inspects)
38420-2C500 entire viscous assy (crap, recomend clutch type locker)
38100-0F56A gear set-final drive (3.692; see Frontier gear sets to upgrade to)
38154-0C0__ washer-adjust, drive pinion (variable part number, won't know until builder inspects)
38120-EC000 bearing-drive pinion, rear
38165-0C020 spacer-housing
38140-0C000 bearing-drive pinion, front
38189-P0117 seal-oil, drive pinion
38210-EC020 flange assy, companion
43262-01P1A nut-drive pinion
38351-0C000 cover rear, final dr (upgrade to Nismo finned LSD rear cover for $50 more; 38351-350DK)
------------------------------------------------------------------
38220-1NC0A flange assy, non LSD both sides

Z, where exactly did you get your diff? I'm guessing the AT needs a different part than the MT?

I bought the whole diff from a nissan mechanic who had it on a G 35.
It cost me 1000.00 for the diff, with out giving him one for trade.
He told me that the parts cost are around 800 to 900 dollars/
I love the diff but there is a huge drop in gas mileage.
at least 20 %. difference at 100km is 700 rpm. 2100 vs 2800.
But the wow feel in 2nd gear is simply awsume. ( go ask the guy in the black N/A carrera that i smoked the other day ) Ya i know a bad thing to do but he asked for it.
Post is in the drag section. My girl friend has grounded me for 2 weeks for doing this.
The rev matching will drive you crazy as its a bit of a pain with these gears.
When i drag the car and shift at 7900 it only drops to 6800 in the next gear, you have to shift quickly or you hiy the lmiter. ( note it 4th gear it will not go past 7600. Its an ecu thing. But on the dyno in 5th it goes up to 8100. With all my bolts ons the car sounds increadable betwenn 7200 to 8100 rpm.
Well worth the 1000.00 dollars.

Thanks for the detailed response! :tiphat:

Sounds like an awesome upgrade, although it may not be for everyone -- the gas mileage has me on the fence -- but the improvement in performance is impressive!

Do you happen to have the part number? (was it listed above in an earlier post?) Was anything else needed for the swap besides diff fluid and gaskets?

installed 4.08 final drive and the car is AWAKE, it is a blast to drive hard now... Its a pretty darn good mod as far as increase in speed and performance go.

But I have a pretty obvious whine from my diff now... I thought this should of been very minimum with the OEM 4.08 final drive. Its pretty loud at 80 and very noticable even crusing as soon as it gets to about 3k RPM... Is this normal ?

the car pulls HARD in second, like ridiculously hard... gears come and go so much faster now though, its noticable...

I am more likely to throw 305s/275s up front now, as I think the added weight and rubber would help... first gear is hard to use now in sub 50 degree weather. Id say of anything I have done, this is the most obvious enhancement.

but this gear whine has me a bit bummed... I need to go back to the shop and see what the deal is with the whine, and how it could be fixed.. From what I understand I should not have noise like I do.. I have a short video going 75-80 on the highway... you can clearly hear it in the video, if anyone cares to hear it, PM me.

I have been eying gears for a while, what is your redline? What speeds do you hit at the top of 2nd and 3rd?

I have since added the M370 motordyne intake manifold and ajusted the fuel curve.
1st gear pulls harder than second gear. ( 2nd gear is insane and 3rd is just as wild.)
I picked up lots of torque and rwhp between 3900 and 7300 rpm. I shift at 7700 rpm, as my limiter is set at 8100.
My tires are 305 35 18 mickey thompson drag radials. No traction isues at all.
GTM is shipping me my 3200 rpm stall converter and i can not imgane how hard it will pull with my stage 2 GTM SC . when i get it on the car.

Guys I have looked over all 10 pages of this post and still have some questions. On a 370 6M what are the cruising speed RPM's (65MPH) in 6th gear for stock,3.9, and 4.08 gears. Also I understand the speedo is not afected and is the SRM affected or not. Please can someone please clarify these? thanks

Z clear your PMs, i have some questions for you about the 4.08s.... :tup:

also Z you use the MT radials for street use ?


PR370Z , I just noted most cruising speeds and what the RPM is at... These are estimates that I am taking from a before and after video that I took, but the difference isnt all that much, but if you cruise at 80-85 I am sure your gas mileage will suffer some what.

STOCK FINAL DRIVE

60 MPH - 2,350 RPM
65 MPH - 2,600 RPM
70 MPH - 2,750 RPM
75 MPH - 2,850 RPM
80 MPH - 3,000 RPM


WITH 4.08s

60 MPH - 2,500 RPM
65 MPH - 2,800 RPM
70 MPH - 3,000 RPM
75 MPH - 3,200 RPM
80 MPH - 3,400 RPM

Crusiing down 19 Miles of Highway at an avg of 69.2 MPH my MPG was 26.1

now im really curious in getting this setup lol

I forgot to mention this in my last post. When I upgraded my final drive I had
to buy another left side flange for the OS Giken (D-NB102061405-S) super lock LSD. The Nissan OEM part is 38220-1NC1B. This flange is longer and has a C-clip on it.

For the AUTO trans guys
 

The whole rear differential part numbers:
370Z, auto trans, 2 pin rear final drive: 38301-EG33D (OCT 08 - AUG 14?)
" Viscous LSD: 38301-EH33D (OCT 08 - AUG 14?)


370Z, auto trans, w/2 pin internal rear differential part numbers:
------------------------------------------------------------------
38220-1NC0A x2 flange assy, right & left side
38342-P9010 x2 seal-oil, diff side
38440-0C000 x2 bearing, diff side
38453-N31__ x2 shim-adjust, side bearing (variable part number, won't know until builder inspects)
38421-0C00A case-differential (this is the open diff, replaces the Viscous LSD or will be replaced w/an aftermarket clutch locker)
38427-0C000 shaft-pinion mate
38425-21W0A pinion-mate
38423-0C00A gear-side
38426-21W00 washer-thrust, pinion mate
38424-0C000 washer-thrust, side gear
38428-U1500 pin-lock, pinion shaft
38225-40P71 circlip-side gear
38102-7S000 bolt, drive gear
38100-0F36A gear set-final drive (3.357; straight cut gears, stronger but whine more; see Frontier gear sets to upgrade to)
38154-0C0__ washer-adjust, drive pinion (variable part number, won't know until builder inspects)
38120-EC000 bearing-drive pinion, rear
38165-0C020 spacer-housing
38140-0C000 bearing-drive pinion, front
38189-P0117 seal-oil, drive pinion
38210-EC020 flange assy, companion
43262-01P1A nut-drive pinion
38351-0C000 cover rear, final dr (upgrade to Nismo finned LSD rear cover for $50 more; 38351-350DK)


370Z, auto trans, w/LSD internal rear differential part numbers:
----------------------------------------------------------------
38220-JK01A flange assy, right side
38220-JK01B flange assy, left side
38342-P9010 x2 seal-oil, diff side
38440-0C000 x2 bearing, diff side
38453-N31__ x2 shim-adjust, side bearing (variable part number, won't know until builder inspects)
38420-2C000 case-differential entire viscous assy (crap, this part is unique to the auto trans LSD and the reason why final drive gears can't just be bolted in; replace this w/an aftermarket clutch locker)
38100-0F36A gear set-final drive (3.357; straight cut gears, stronger but whine more; see Frontier gear sets to upgrade to)
38154-0C0__ washer-adjust, drive pinion (variable part number, won't know until builder inspects)
38120-EC000 bearing-drive pinion, rear
38165-0C020 spacer-housing
38140-0C000 bearing-drive pinion, front
38189-P0117 seal-oil, drive pinion
38210-EC020 flange assy, companion
43262-01P1A nut-drive pinion
38351-0C000 cover rear, final dr (upgrade to Nismo finned LSD rear cover for $50 more; 38351-350DK)

I know it is a completely different make/model but my 1993 Lightning came stock with 4.10 gears and it definitely has a whine. I would assume it's a fact of life since it has 50k miles on it and runs perfect.