4.08 Gear Install (7AT) Review

1slow370 · 05-28-2014, 12:43 PM

Quote:

Originally Posted by blumango

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!

Shi'1+e...I ordered my 4 T3rdy's over a year ago...

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

Don't FE4R teh GE4R! Good tires and suspension r K3y!

Shi'1+e...I ordered my 4 T3rdy's over a year ago...

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

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

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: wstar's Journal

1slow370 · 05-29-2014, 05:18 PM

Quote:

Originally Posted by Taylortoons

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

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

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

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

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

DEpointfive0 · 05-30-2014, 03:31 AM

Quote:

Originally Posted by 1slow370

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

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?

05-29-2014, 01:20 AM	#122 (permalink)
L33T Z34 Banned Join Date: Jun 2010 Location: Ahnald, MO Age: 46 Posts: 387 Drives: 09 K51 G C Bw/S 6MT Rep Power: 0	Don't FE4R teh GE4R! Good tires and suspension r K3y! Shi'1+e...I ordered my 4 T3rdy's over a year ago... 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! Last edited by L33T Z34; 05-29-2014 at 01:28 AM. Reason: 7AT, more comments

05-29-2014, 01:41 PM	#123 (permalink)
NickD A True Z Fanatic Join Date: Mar 2012 Location: Babylon, NY Posts: 1,322 Drives: 10 Z34 Touring Vert Rep Power: 15	I went with a Quaife diff and 4.08 gear on my 7AT....amaze balls! __________________ 2010 370z Touring Roadster Monterey Blue My Z Photo Library

05-29-2014, 03:54 PM	#126 (permalink)
Taylortoons Base Member Join Date: Aug 2013 Location: Dallas Posts: 98 Drives: 11 370Z AT PW Rep Power: 11	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? NickD likes this.

05-29-2014, 07:46 PM	#129 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	^ 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 Felix 808 likes this. __________________ 7AT Track Car! Journal thread / Car setup details

05-30-2014, 05:38 AM	#135 (permalink)
DjSquall A True Z Fanatic Join Date: Apr 2010 Location: Tottenham, ON Age: 36 Posts: 1,340 Drives: My first car Rep Power: 22	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? __________________ My Z did p0rn

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