Nissan 370Z Forum - 4.08 Frontier gear swap

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- - 4.08 Frontier gear swap (http://www.the370z.com/engine-drivetrain/18209-4-08-frontier-gear-swap.html)

did you find info for the gear swap for your 7AT, I'm interested as well....

Quote:

Originally Posted by jdonadio (Post 1371845)

did you find info for the gear swap for your 7AT, I'm interested as well....

Back from the death!!

Would Also like to know about this gears on 7AT
Anyone would chime in??? :confused:

Quote:

Originally Posted by AggieAv8r (Post 1345804)

agreed - I'm still technically "breaking them in" but I have access to a runway where I'll soon test 'em out. But practically speaking, no, no noticeable difference. The car just feels like it needs to keep going .... so fun to drive now.

On the downside, and I'm hoping maybe jnaut and tranceformer will chime in, I talked to the shop that put em in today. Told him about the whine under light acceleration, just enough drive input to maintain speed, and he acted like there was nothing more he could do - he said the mesh pattern was perfect, and then gave me the dreaded "some gear sets just whine ... can't tune em out"

Told me to drive it for awhile and let everything "seat" and see if it changes any. I'm also going to switch to Redline 75W90 to see if it helps any. But I don't think it will. Any reason to believe that this may work itself out after break in ???? That just doesn't make sense to me ....

So I'm hoping you guys can give me some ammo to go back with ... as far as specific adjustments. Anyone else see this? Any experience with pinion preload adjustments? Mesh patterns that work better than others i.e. more toe, or more heel patterns? Anything that will convince him to break into it again and make an adjustment.

I found this thread (and forum) via a search trying to find if the pinion sleeve and nut came with the gear set.

I have had these and a quaife in my 06 350Z for over a year/10k and just started whining horribly. It started as you described.

My differential was assembled by a shop that had no clue and is now out of business. They did not replace anything but the ring and pinion and apparently did not properly set the preload. It is currently at a shop that only deals in diffs, transfer cases and transmissions.

As I did not want to lose my car I swapped the open base diff back in. WHAT A DIFFERENCE.

Luckily it looks like there was no damage.

http://i20.photobucket.com/albums/b2...o/f5d4f442.jpg

http://i20.photobucket.com/albums/b2...o/0129a271.jpg

http://i20.photobucket.com/albums/b2...o/49355832.jpg

http://i20.photobucket.com/albums/b2...o/11085c4f.jpg

282.02 (with a discount) in differential rebuild parts.

http://i20.photobucket.com/albums/b2...o/b6397b19.jpg

FYI....We run this final drive in our RC in t Conti challenge. Final drive seap is one of yhe bestbthing you can do for improved acceleration...espc for a track car.

any word on this for the 7at?

After reading this thread, this is now on my short list of mods to do to the Nismo. I would imagine this would be one of the very best things to do if you're staying with straight bolt ons. I'm kind of surprised no one has come up with an ecu flash to adjust the issues with SRM (I would assume since its not a mechanical thing, this could be programmed somehow.)

Good info.

(I'm gonna look and see if there are any reviews of the 4.3 FD.)

I've got the 4.36 final drive sitting on the shelf in my garage. I can't wait to get this installed w/the polyurethane rear diff mounts over the upcoming winter.

Quote:

Originally Posted by Nuki (Post 1795513)

I asked Uprev about this and they said that currently they are not able to change the shift points for the SRM, but would look in to it. This was several months back and I'm pretty sure nothing came of it.

It seems to me if a good shop would offer installed packages there would be lots of demand. This is what happened in the S2000 community and it worked great. A quick search shows lots of doner diffs out there so getting a core isn't as bad as it was for the S2000. This allows you to buy a core and send it off to get the work done and not be down while getting the gears installed. The shop could install a good LSD while in there as well. Hopefully this has already happened and I just haven't read about it yet.

What's a rough estimate of what a good shop can be expected to charge for installing new gears?

Quote:

Originally Posted by babbagandu (Post 1813785)

What's a rough estimate of what a good shop can be expected to charge for installing new gears?

depends on the shops hourly charge and how long it takes them

just ask the shop you have in mind how much it would cost and they should be able to help you out

ON TOPIC
is there a noticeable difference with taller gears?

Quote:

Originally Posted by luigi90210 (Post 2037570)

I'm getting 4.08s installed next week on Dec. 6th on my 7AT. I will do a full review on them. As for price I got quoted 500 bucks.

Quote:

Originally Posted by dthem370 (Post 2038124)

I'm getting 4.08s installed next week on Dec. 6th on my 7AT. I will do a full review on them. As for price I got quoted 500 bucks.

im looking forward to your review, i have a 6MT but i personally dont know much about gearing aside from taller gears make you accelerate faster, and shorter gears make your top speed higher

any real world gains by doing a mod like this? and will SRM work after this, if not than can a tune fix SRM?

Quote:

Originally Posted by luigi90210 (Post 2039598)

Based on my research, SRM will be off by like 300 RPMS for the manuals and people say they don't even realize it that much. There is no fix for that as far as I know. Also, someone reported the SRM will automatically turn off once you exceed speeds around 120MPH, but after turning the car off and back on it works fine again.

The gears (4.08s) will make you accelerate much faster. It can take off a few tenths of your quarter mile time and improve your 60' times.

You will lose top end speed, meaning you can know only go to something like 180mph instead of like 200mph. Realistically I don't think any of us will ever go that fast so that's not much of a concern for me.

You will lose some MPG because your RPMs will be higher (500RPMs higher) when cruising around, especially on the freeway. I personally don't mind it b/c if I was concerned about MPG I wouldn't have bought the Z in the first place.

The hardest thing is keeping traction with the gears from what I read. So make sure if you upgrade the gears to have a good set of tires and a good differential (stock VLSD at the minimum).

I will post more info soon when I create my review.

Quote:

Originally Posted by dthem370 (Post 2038124)

I'm getting 4.08s installed next week on Dec. 6th on my 7AT. I will do a full review on them. As for price I got quoted 500 bucks.

Can you list what all parts you bought and from which vendor?
Are you keeping the stock vlsd or aftermarket LSD like os given or quaife?