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-   -   4.08 Gear Install (7AT) Review (http://www.the370z.com/engine-drivetrain/64127-4-08-gear-install-7at-review.html)

1slow370 05-28-2014 12:43 PM

Quote:

Originally Posted by blumango (Post 2561497)
Must I really get a sport manual pumpkin? I have the sport 7AT with VLSD. Can I use a non-sport manual pumpkin and swap my VLSD over?

nope the vlsd is built into the ring gear carrier, the automatics have a different sized ring gear so you can't put any of the larger gears on the automatic vlsd carrier. if you by an open manual diff you are stuck with open unless you get an aftermarket lsd or buy a manual vlsd gear carrier and swap it. it should be noted that when you change te carrier you also need to buy bearings and shims and have a shop shim the diff.

L33T Z34 05-29-2014 01:20 AM

Don't FE4R teh GE4R! Good tires and suspension r K3y! :icon17: Shi'1+e...I ordered my 4 T3rdy's over a year ago...:icon14:
0! I see 7AT, I don't recommend theez for it...prob 3.90z for 7AT....
LuLz, g00d luck to any1 will'n 2 Mport a JDM rear end to teh USA....prob b cheeeper to build ur MT rear end w/4.36s and clutch LSD, then 2 pay for dat used JDM shi'1te! Just say'N....Mport, u still get an open diff?!....F4IL!

NickD 05-29-2014 01:41 PM

I went with a Quaife diff and 4.08 gear on my 7AT....amaze balls!

1slow370 05-29-2014 01:46 PM

Quote:

Originally Posted by L33T Z34 (Post 2838014)
Don't FE4R teh GE4R! Good tires and suspension r K3y! :icon17: Shi'1+e...I ordered my 4 T3rdy's over a year ago...:icon14:
0! I see 7AT, I don't recommend theez for it...prob 3.90z for 7AT....
LuLz, g00d luck to any1 will'n 2 Mport a JDM rear end to teh USA....prob b cheeeper to build ur MT rear end w/4.36s and clutch LSD, then 2 pay for dat used JDM shi'1te! Just say'N....Mport, u still get an open diff?!....F4IL!

Please tell me you're kidding around with this, otherwise I vote it for most unreadable post of the year.

Chuck33079 05-29-2014 01:49 PM

Quote:

Originally Posted by 1slow370 (Post 2838825)
Please tell me you're kidding around with this, otherwise I vote it for most unreadable post of the year.

No, he always types like that. I don't even know what that post says. It's a really strange dichotomy- usually good tech info delivered in a style reminiscent of a 12 year old special needs kid on XBox Live.

Taylortoons 05-29-2014 03:54 PM

Thinking about going this route. Just to make sure I'm reading the posts correctly. I have a base 2011 7AT with open diff. The Quaife lsd and 4.08 will drop into the pumpkin and require only shims?

wstar 05-29-2014 05:01 PM

Quote:

Originally Posted by 1slow370 (Post 2837152)
nope the vlsd is built into the ring gear carrier, the automatics have a different sized ring gear so you can't put any of the larger gears on the automatic vlsd carrier. if you by an open manual diff you are stuck with open unless you get an aftermarket lsd or buy a manual vlsd gear carrier and swap it. it should be noted that when you change te carrier you also need to buy bearings and shims and have a shop shim the diff.

Note that most of what makes this situation suck is that the 7AT's stock ring gear is 10mm thicker than the normal ones (as found in the 6MT), and the part of the VLSD carrier that it rides on is thus 10mm thinner to compensate and keep everything centered or whatever. If you were to buy an aftermarket LSD meant for a 6MT to go with your 4.08's, you could drop the 4.08's + 6MT LSD into your 7AT+Sport housing (modulo unequal shaft-length issues from LSD-vs-not). I posted some related findings around here: http://www.the370z.com/members-370z-...ml#post2745993

1slow370 05-29-2014 05:18 PM

Quote:

Originally Posted by Taylortoons (Post 2839062)
Thinking about going this route. Just to make sure I'm reading the posts correctly. I have a base 2011 7AT with open diff. The Quaife lsd and 4.08 will drop into the pumpkin and require only shims?

You will also need the bearings and seals and crushwasher and all the other little pieces for installing the gears.

I wish we could just sticky "Rear-ends are precision gear assemblies and NOTHING inside them is drop in. You will need bearings, seals, lots of shims, crush washers and other stuff, as well as significant labor time at a shop that specializes in this work. You CAN do it yourself but you will probably screw it up and turn everything you just bought into expensive paperweights"

wstar 05-29-2014 07:46 PM

^ Very true. My only experience with rear ends was on an IH Scout a friend was working on several years ago. We decided to buy new gears and put them in ourselves. Keep in mind this is a big, ancient SUV/Truck type thing where everything is easy to work on.

The first full day with 3 guys on the project (none of us had done this kind of thing before, but we're all very experienced at any normal DIY mechanic stuff short of engine/diff/trans rebuilds, and we had a 2-post lift to work on) was a complete mess just learning what was going on during re-assembly, and realizing we didn't have enough of the correct shims, and that we had already crushed the crush bushing/washer thing for the pinion down flatter than it should be, etc, and that the one cheap dial gauge we had wasn't nearly enough in terms of taking repeatable measurements of the right kinds.

After ordering more bits and tools, we went back at it again for a full weekend (well, minus time spent drinking between) trying to get the thing reinstalled correctly. It was a long repetitive process of putting it in, seeing a problem with measurements and/or the grease pattern on the gears, pulling it back out and adjusting some shims, trying again and get wildly different results than we expected from the shim adjustments, etc.

Eventually we did make it work, but 3 guys x 3 days was totally not worth it vs just taking it down to a gear shop that does this stuff every day and paying them to do it right. Shortly after that I had to do a similar job on my '99 Trans Am. Dropped it off at a shop that specializes in diff/trans work and they had it back to me the next day working perfect for something like $500.

I'm all for encouraging people to take on DIY projects and do things themselves, because it's usually worth the learning process, but... if you're ready to tackle a diff install, you'd know it, and if you don't know it, don't bother :)

blueranger 05-29-2014 11:18 PM

Quote:

Originally Posted by Taylortoons (Post 2839062)
Thinking about going this route. Just to make sure I'm reading the posts correctly. I have a base 2011 7AT with open diff. The Quaife lsd and 4.08 will drop into the pumpkin and require only shims?

Save time and money... Just swap your rear diff for a manual vlsd pumpkin and buy the Z1 diff swap kit that gives you the Nismo finned cover, motul oil & Whiteline bushings. Just swapped and the 3.69 gears with VLSD feels great on my 7AT!

1slow370 05-30-2014 03:07 AM

Quote:

Originally Posted by blueranger (Post 2839601)
Save time and money... Just swap your rear diff for a manual vlsd pumpkin and buy the Z1 diff swap kit that gives you the Nismo finned cover, motul oil & Whiteline bushings. Just swapped and the 3.69 gears with VLSD feels great on my 7AT!

this^ it literally takes me 3 hours on jackstands including the rear bushing removal

DEpointfive0 05-30-2014 03:12 AM

Quote:

Originally Posted by 1slow370 (Post 2839684)
this^ it literally takes me 3 hours on jackstands including the rear bushing removal

I might have witnessed this.

1slow370 05-30-2014 03:20 AM

Quote:

Originally Posted by DEpointfive0 (Post 2839686)
I might have witnessed this.

LOL at "might have" on a side note I was upset that you got your rear rotors changed before I got your diff instaled, but I account that to showing you the wrench trick so I still win :p

DEpointfive0 05-30-2014 03:31 AM

Quote:

Originally Posted by 1slow370 (Post 2839688)
LOL at "might have" on a side note I was upset that you got your rear rotors changed before I got your diff instaled, but I account that to showing you the wrench trick so I still win :p

Lol, I definitely sat on my áss more than you did though.


But I know I'll always lose a race to you, lol
On another note, I almost died today because my tires weren't hot enough to come out of that slide at work, LOOOOL
But god damn do I like that diff

DjSquall 05-30-2014 05:38 AM

I have a 7AT into which I just swapped in the quaife diff in place of the factory VLSD. does anyone know if I can fit the 4.08 gears on it?


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