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E85 Z4 diff swap

2003 - 2009, roadster, coupe, facelift
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GaryT
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E85 Z4 diff swap

Post by GaryT » Sun Feb 01, 2015 4:05 pm

E85 Z4 diff swap

I recently installed a Mfactory lsd in my E85 3.0, although there are a few threads on installing the lsd in the diff case, there was no guide on a Z4 diff swap that I could find, I had looked high and low on the Internet, so I thought I would post a thread of how i did it, to help those here wanting to install a lsd or simply to change differentials.
I was lucky enough to have a donor diff for the install of the mfactory lsd, so the following is just the diff swap as per topic title.
With several cups of tea and a good old cornish pasty it took me 6.5 hours in total.

Tools:
E12 torx socket x 3/8 drive plus extension & 3/8 x 1/2 drive adapter
13mm hex socket
16mm hex socket
18mm hex socket
21mm hex socket
Torque wrench
Scissor jack


Remove skid pan with aero duct for diff cooling - 8mm hex screws ?ft/lbs
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Remove reinforcement plate - 13mm & 16mm nut ?ft/lbs & 2x8mm hex screw from heatshield
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Remove pushrod bracket - 18mm nut ?ft/lbs
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Remove Exhaust hangers and let it dangle - 13mm nut ?ft/lbs
Image
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Remove anti-roll bar - rear bracket 13mm nut & bolt (16 ft lbs), front bracket 13mm nut & bolt. (25 ft lbs)
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Remove both pull rod braces - 18mm nut 57 ft-lbs, 13mm bolt 22 ft-lbs
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Disconnect the input shaft from the differential - 4 E12 Torx Bolts 61 ft-lbs & disconnect output shafts and tie up withwire/string. Each axle has 6 E12 external Torx bolts 59 ft-lbs
Image

Remove the Differential - Support the differential with a jack. The Differential is held by 3 bolts. 2x18mm bolts in the front & 1x21mm bolt on the rear. Remove the 2 front ones first, then remove the rear one. 18mm Bolts 70 ft-lbs, 21mm Bolt 128ft-lbs

Reversal for install of diff. Where i haven't stated a torque figure i just did them up to what i thought was appropriate because i couldnt find a torque figure online, any help with this would be appreciated.

Any comments or crticism welcome, I just hope this inspires people to do the lsd install as it really makes such a difference to how the car behaves :thumbsup:

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ekimj10
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Re: E85 Z4 diff swap

Post by ekimj10 » Sun Feb 01, 2015 4:51 pm

You have made it sound a fairly simple job, but an excellent write up/pictures nonetheless.
I'm assuming it was done at home without the aid of a high-lift garage jack?
Thanks for sharing.
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Brasseye
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Re: E85 Z4 diff swap

Post by Brasseye » Sun Feb 01, 2015 5:02 pm

Great write up...
Shame the e89 35i didn't have lsd.
Thanks for sharing :thumbsup:

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Grumpyowl
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Re: E85 Z4 diff swap

Post by Grumpyowl » Sun Feb 01, 2015 5:17 pm

Not something I'm planning to do, but good job well done :thumbsup:
Good write up too :thumbsup: :thumbsup:

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GaryT
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Re: E85 Z4 diff swap

Post by GaryT » Mon Feb 02, 2015 11:11 am

ekimj10 wrote:You have made it sound a fairly simple job, but an excellent write up/pictures nonetheless.
I'm assuming it was done at home without the aid of a high-lift garage jack?
Thanks for sharing.
Hi, im lucky enough to have access to a pit, but i know Yorkie did his on ramps in a carpark lol

Image

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Bazoz4
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Re: E85 Z4 diff swap

Post by Bazoz4 » Thu Feb 05, 2015 3:44 pm

Great write up and pics, thanks for sharing. Baz :thumbsup: :driving:
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AaronMaguire
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E85 Z4 diff swap

Post by AaronMaguire » Mon Oct 24, 2022 10:52 pm

This is perfect to find this.
My Diff has just failed on me and I need to change it but I can't find any manuals on the process.
Time to find a pit garage to hire.

Great write up although quite daunting. lol
MY04 Z4 3.0 Manual.
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True-Blue
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E85 Z4 diff swap

Post by True-Blue » Mon Oct 24, 2022 11:22 pm

AaronMaguire wrote: Mon Oct 24, 2022 10:52 pm This is perfect to find this.
My Diff has just failed on me and I need to change it but I can't find any manuals on the process.
Time to find a pit garage to hire.

Great write up although quite daunting. lol
My local garage did a diff swap on an E85 for £100 cash. I do lot’s of jobs myself, but was very happy to pay this to avoid the hassle as I don’t have a pit.
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Previous Z4’s :E89 30i, E89 20i, E85 3.0Si (X4) E85 3.0i, E86 3.0 Si, E85 2.5si, E85 2.5i

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AaronMaguire
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E85 Z4 diff swap

Post by AaronMaguire » Mon Oct 24, 2022 11:33 pm

Wow I wish it was that cheap over here in Melbourne. I'm struggling to find a diff. the 3.07 is super rare and the 3.46 is more available. The LSD over here is like hens teeth. haha.
MY04 Z4 3.0 Manual.
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AaronMaguire
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E85 Z4 diff swap

Post by AaronMaguire » Tue Oct 25, 2022 2:02 am

Anyone had issues with fitting 3.46:1 ratio Diffs to a 3.0 manual that takes the 3.07 as standard?
MY04 Z4 3.0 Manual.
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AaronMaguire
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E85 Z4 diff swap

Post by AaronMaguire » Thu Nov 17, 2022 8:51 am

So, a 330i M54 3.46 diff does NOT fit a 2004 e85 3.0 manual z4.
My mechanic has just informed me today and the diff I bought from BMs R US refuse to refund.
This totally sucks
MY04 Z4 3.0 Manual.
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Madcatgrafix
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E85 Z4 diff swap

Post by Madcatgrafix » Wed Nov 30, 2022 1:58 pm

Great write up. Actually looking for a lower geared 2.2i diff unit myself, to fit a new lsd into, to perk up my 3l.
2003 Z4 3l winter runabout :driving:
2013 370z motorsport (my long term project)
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