VHR + FD Gear Ratio upgrades - 3.9 and 4.08

Zat_Zuma · 02-03-2011, 11:34 AM

Quote:

Originally Posted by chuckd05

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

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.

Whine is not good. I bet you have spun your wheels and created axle hop. Can't miss it ....... sounds like a set pounding drums coming from the rear end and you swear it's going to fall apart. Either way, it sounds like the pinion gear is out of adjustment (bushing may have pounded out) or you have damaged a side carrier bearing from the axle hop.

Unfortunately, the only way to be be sure is to pull the rear diff and perform a inspection of the bearings and clearances. Chances are a rebuild will be necessary.

I had a severe case of axle hop on the drag strip and damaged the rear diff, as it now has gear whine, as you have described. I'm rebuilding it this spring and looking into rear diff braces and solid mount kit.

chuckd05 · 02-04-2011, 08:08 AM

I had the shop replace every bearing and bushing during the install , the shop re opened it and adjusted the backlash. The whine is now very very vague. Almost non existent, I should of posted that earlier.

On occasion you can here a very minute whine. They said the Case and available shims just couldn't be perfect but that all measurements are well within spec. I trust them. Its about 5 percent of what it was originally, so far no problems.

Never experienced axle hop. The car spins fine, no wheel hop either.

Zat_Zuma · 02-04-2011, 08:44 AM

No matter what they say about gear whine being within specs, its bogus.
The backlash (pinion gear) is out and needs to be redone. The amount of different shims available for the diff makes the excuse given; bogus. The adjustments are time consuming and require very meticulous measurements. My diff had zero issues and no whine at all until I broke it.
The clearances were done to my specifications and the backlash was perfect. It took the master technician a full day to rebuild it and to get it right.

With the 4.083 gears the clearances and backlash must be better than factory specs or you will get a small amount of gear whine. Compare the factory specs on a frontier with 4.083 gears, 350Z with 3.5 gears and our 370Z's with 3.7 gears and look at the differences.

But since you trust your shop and seem to be happy with their work, I really don't see why you are complaining if your leaving out imortant info and are satisfied with what you have.

chuckd05 · 02-05-2011, 02:50 AM

Well it was bad at first. Than they opened it and it improved to a large degree. I am not a genius on rear ends or proper backlash specs. I am always learning and will run it by the shop again.

L33T Z34 · 02-15-2012, 11:49 AM

For future reference...
What to look for in JDM salvage importer stock if buying used.

JDM whole rear differential, R200(V), with lower final drive gears!

2005-2006 Skyline sedan w/VQ35DE and CVT
JDM part number: 38301-2C807 (4.363 final drive; has the 350Z/G35 axle flanges)

2007-2012 Skyline sedan w/VQ25HR
JDM part number: 38301-EH64A (3.916 final drive)

L33T Z34 · 10-09-2012, 12:35 PM

I got a chance to take pictures of my 3.90 and 4.36 ring and pinions.

3.916 FD = part number 381000B66A
4.363 FD = part number 381000C860

G37Sam · 04-08-2013, 07:53 AM

Hey Leet,

Where'd you buy the 4.363 ring and pinion from?

Wonka2581 · 04-09-2013, 04:54 PM

Sub'd for future reference.

L33T Z34 · 08-26-2013, 10:34 PM

Quote:

Originally Posted by G37Sam

Hey Leet,

Where'd you buy the 4.363 ring and pinion from?

A nissan dealer! It's that EASY! Don't let these "perfomance shops" fool u!

G37Sam · 08-27-2013, 04:19 PM

Better late than never I guess haha

andre12031948 · 10-31-2013, 05:26 PM

Quote:

Originally Posted by Zat_Zuma

No matter what they say about gear whine being within specs, its bogus.
The backlash (pinion gear) is out and needs to be redone. The amount of different shims available for the diff makes the excuse given; bogus. The adjustments are time consuming and require very meticulous measurements. My diff had zero issues and no whine at all until I broke it.
The clearances were done to my specifications and the backlash was perfect. It took the master technician a full day to rebuild it and to get it right.

With the 4.083 gears the clearances and backlash must be better than factory specs or you will get a small amount of gear whine. Compare the factory specs on a frontier with 4.083 gears, 350Z with 3.5 gears and our 370Z's with 3.7 gears and look at the differences.

But since you trust your shop and seem to be happy with their work, I really don't see why you are complaining if your leaving out imortant info and are satisfied with what you have.

"until I broke it" You need 600h.p + wide low air pressure slicks & come out of a standing start at over 6,000 rpm to maybe break a well installed ring & pinion set. What I'm saying is obvious, so I'll leave it there.

Zat_Zuma · 10-31-2013, 06:17 PM

What is this?

Better late than never at all

Sorry, but I've been trapped in a time warp

That was written in 2011, Feb

Where the frick have you been???

andre12031948 · 10-31-2013, 06:23 PM

Quote:

Originally Posted by Zat_Zuma

What is this?

Better late than never at all

Sorry, but I've been trapped in a time warp

That was written in 2011, Feb

Where the frick have you been???

I went from last back

blumango · 11-13-2013, 05:23 AM

Hi,

Does anyone know what the correct space between the gears should be? Without this info, I won't know how much I should shim.

Please advise.

Thanks.

Wonka2581 · 11-13-2013, 07:12 AM

Quote:

Originally Posted by blumango

Hi,

Does anyone know what the correct space between the gears should be? Without this info, I won't know how much I should shim.

Please advise.

Thanks.

I have no clue but if I were you I would take it to someone who knows what they are doing. I know if you don't have the backlash set right you will have catastrophic failure. Just my $0.02

Sent from my iPhone using Tapatalk

02-04-2011, 08:08 AM	#152 (permalink)
chuckd05 A True Z Fanatic Join Date: Oct 2009 Location: NY Posts: 2,391 Drives: No longer a Z Rep Power: 20	I had the shop replace every bearing and bushing during the install , the shop re opened it and adjusted the backlash. The whine is now very very vague. Almost non existent, I should of posted that earlier. On occasion you can here a very minute whine. They said the Case and available shims just couldn't be perfect but that all measurements are well within spec. I trust them. Its about 5 percent of what it was originally, so far no problems. Never experienced axle hop. The car spins fine, no wheel hop either. __________________ 09 370Z 6M PW - FBO Best 1/4 mile = 12.926 @ 109 SOLD -- 08 BMW 135i - FBO 12.1@120mph SOLD -- white 09 e92 335 Coupe Mtech - 11.9 @ 119 :-) Last edited by chuckd05; 02-04-2011 at 08:12 AM.

02-04-2011, 08:44 AM	#153 (permalink)
Zat_Zuma A True Z Fanatic Join Date: Nov 2008 Location: Edmonton, Alberta ...eh Posts: 1,171 Drives: 2017 Touring auto Rep Power: 19	No matter what they say about gear whine being within specs, its bogus. The backlash (pinion gear) is out and needs to be redone. The amount of different shims available for the diff makes the excuse given; bogus. The adjustments are time consuming and require very meticulous measurements. My diff had zero issues and no whine at all until I broke it. The clearances were done to my specifications and the backlash was perfect. It took the master technician a full day to rebuild it and to get it right. With the 4.083 gears the clearances and backlash must be better than factory specs or you will get a small amount of gear whine. Compare the factory specs on a frontier with 4.083 gears, 350Z with 3.5 gears and our 370Z's with 3.7 gears and look at the differences. But since you trust your shop and seem to be happy with their work, I really don't see why you are complaining if your leaving out imortant info and are satisfied with what you have. __________________ [B]2009 & 2017 370Z Touring Sport Autos SOLD Last edited by Zat_Zuma; 02-04-2011 at 03:54 PM.

02-05-2011, 02:50 AM	#154 (permalink)
chuckd05 A True Z Fanatic Join Date: Oct 2009 Location: NY Posts: 2,391 Drives: No longer a Z Rep Power: 20	Well it was bad at first. Than they opened it and it improved to a large degree. I am not a genius on rear ends or proper backlash specs. I am always learning and will run it by the shop again. __________________ 09 370Z 6M PW - FBO Best 1/4 mile = 12.926 @ 109 SOLD -- 08 BMW 135i - FBO 12.1@120mph SOLD -- white 09 e92 335 Coupe Mtech - 11.9 @ 119 :-)

02-15-2012, 11:49 AM	#155 (permalink)
L33T Z34 Banned Join Date: Jun 2010 Location: Ahnald, MO Age: 47 Posts: 387 Drives: 09 K51 G C Bw/S 6MT Rep Power: 0	JDM R200(V) part numbers For future reference... What to look for in JDM salvage importer stock if buying used. JDM whole rear differential, R200(V), with lower final drive gears! 2005-2006 Skyline sedan w/VQ35DE and CVT JDM part number: 38301-2C807 (4.363 final drive; has the 350Z/G35 axle flanges) 2007-2012 Skyline sedan w/VQ25HR JDM part number: 38301-EH64A (3.916 final drive) fuct likes this.

04-08-2013, 07:53 AM	#157 (permalink)
G37Sam A True Z Fanatic Join Date: Dec 2008 Location: Dubai, UAE Posts: 1,507 Drives: RB'd G37 Rep Power: 20	Hey Leet, Where'd you buy the 4.363 ring and pinion from? __________________ '14 Viper GTS '08 RB'd G37S - Sold

04-09-2013, 04:54 PM	#158 (permalink)
Wonka2581 A True Z Fanatic Join Date: Nov 2012 Location: Chattanooga, TN Posts: 3,083 Drives: MY WIFE CRAZY.... Rep Power: 2612	Sub'd for future reference. __________________ "I have nothing to offer but blood, toil, tears and sweat""Winston Churchill"

08-27-2013, 04:19 PM	#160 (permalink)
G37Sam A True Z Fanatic Join Date: Dec 2008 Location: Dubai, UAE Posts: 1,507 Drives: RB'd G37 Rep Power: 20	Better late than never I guess haha __________________ '14 Viper GTS '08 RB'd G37S - Sold

10-31-2013, 06:17 PM	#162 (permalink)
Zat_Zuma A True Z Fanatic Join Date: Nov 2008 Location: Edmonton, Alberta ...eh Posts: 1,171 Drives: 2017 Touring auto Rep Power: 19	What is this? Better late than never at all Sorry, but I've been trapped in a time warp That was written in 2011, Feb Where the frick have you been??? __________________ [B]2009 & 2017 370Z Touring Sport Autos SOLD Last edited by Zat_Zuma; 10-31-2013 at 06:19 PM.

11-13-2013, 05:23 AM	#164 (permalink)
blumango Base Member Join Date: Mar 2013 Location: Singapore Posts: 75 Drives: 2010 370Z Roadster Rep Power: 12	Hi, Does anyone know what the correct space between the gears should be? Without this info, I won't know how much I should shim. Please advise. Thanks.

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