DIY - Limited Slip Differential Install
 

Disclaimer, these are my opinions and the way I did mine. Use this information at your own risk.

First off, just because your rear diff bushing leaked the fluid out of it does not mean it needs to be addressed immediately. If you your getting a knocking noise it does, otherwise you have time. I ran mine for about 6 weeks after noticing the leak (actually pointed out to me by a forum member) and found it to be still solid when I cut it out (what a pain BTW).

I finally received all the parts last week and started the install this past weekend. This turned out to be a bigger job than I expected but I think the worst is behind me. I don't have my notes with me so I'll be updating the thread over the next couple of days with pics and info.

Parts List:
OS Gicken (NS112-HA) Super Lock Limited Slip Differnetial - $1605.50 (Z1 Motorsports)
Z1 370Z/G37 Full Differential Upgrade Kit (w. Motul 75W140) - $290 (Z1 Motorsports)
...Energy Differential Bushings - DO NOT USE, requires modifications
OEM 370Z Differntial Output Shaft $176.32 (Z1 Motorsports) WRONG PART - DO NOT USE (Not OEM, Missing Threads)
... To use part, Mr Metric: 6x #M50202 @ .55 ea and 6x M41459 @ $1.64 ea, torque to 60 ft-lb due to grade 10.9
OEM Diff Side Bearing (38440-0C000) 2x for $97.96 (Z1 Motorsports)
OEM Diff Side Seal (38342-P9010) 2x for $19.96 (Z1 Motorsports)
OEM Diff LSD to Pinion Bolt Z33 10x for $26.60 (Concept Z Performance)
1x, 20692-65J00, $16.07 Mid Section Exhaust Gasket front (Capitol Nissan of San Jose)
2x, 20692-1E810, $11.99 ea Mid Section Exhaust Gaskets 2 rear (Capitol Nissan of San Jose)
4x, 08918-3401A, $1.67 ea exhaust nuts to replace damaged ones (Capitol Nissan of San Jose)

Special Tools:
Torque Wrench
17mm deep socket (2" dp, preferably 1/2" drive)
Breaker bar
Indicator and Indicator mount for backlash measurement

Torque Specs (updated)
Ring Gear 58 ft-lbs +31to36 deg (some threads say use threadlocker, Nissan spec didn't mention it, old ones where clean, I left them clean)
Diff Cover 44 ft-lb
Diff Cover Plugs 35 ft-lbs
Half-Shaft (Diff side) 59 ft-lbs
Drive Shaft 55 ft-lbs
Fill plugs - 26 ft lbs
Front mount bolts - 74 ft - lbs
Rear cover stud - 81 ft - lbs
Bearing cap - 69 ft lbs


Basic order of operation:
Remove Cross Brace
Remove Mid section of exhaust
Remove Sway Bar
Disconnect Half-Shaft Sensors
Drain Oil
Mark and disconnect half shafts
Disconnect Drive Shaft
Remove Differential
Check Backlash
Swap LSD
Reverse order for install

Thanks for the support:
Jon at OS Giken for great support and super fast email responses
Jon&Joel at Z1 Motorsports
Capital Nissan of San Jose for torque specs, took forever but they came through

Removal part1
 

Mark Half-shaft orientation
Mark Drive-shaft orientation (mine was marked well enough from the factory)
Half shaft sensor - remove and hang away over sub-frame where it won't get crushed
Disconnect vent tube (top of diff)

Removal Part 2
 

The dreaded rear differential mount - Lets just say it lived up to it's reputation. The only thing torn on it was the thin piece of rubber holding the fluid in. It would of lasted a long time still before becoming an issue.
See: http://www.the370z.com/diy-section-d...-bushings.html (it took me longer)

Rework Differential Part 1
 

Bushing Removal
Cover Removal
Half-Shaft Stub Removal
Backlash - Pre-Measurement
Bearing Cap Removal

Rework Differential Part 2
 

Bearing Press - Easier than expected, used 20 ton press (BTW, The Pipe T was modded before use, ID increased & Ends leveled). Super important to only press on the inner race!
Marked the outer race bags and installed them when ready. Didn't want them to fall off and get dirty.
Rebagged the differntial once the bearings where on untill it was ready for the ring gear.
Bolt torque + 31-36 degrees

Install
 

Backlash Post Measurement, got lucky like most people, backlash only changed ~.0005" (from .004 to .0035, not going to mess with it)
Gear Marking Grease - looks good to me. Went forward - took picture, then backwards took picture (driving by hand on front shaft)
How to read pattern: ALLDATAdiy.com - 2001 Ford Escort ZX2 L4-2.0L DOHC VIN 3 - Checking Tooth Contact Pattern & Condition of Ring and Pinion
Installing the stub-shafts - My OS Giken came with the spring clips already inside the LSD. I needed to remove them from the stub shafts prior to install. Put the differential on it's side and center the clip in it's cavity prior to installing the stub shaft. I will allow it to snap in easily.
Install Cover - Make sure you clean it before putting it on. My cover had a bunch of aluminum shavings in it...nice.\
Permatex grey came with kit, clean surfaces and follow directions. (use alcohol, lacquer thinner (my favorite) or acetone for final wipe)
Install Rear stud (used blue Loctite) and fill with gear oil
Rear bushing gets installed from the front, lube it up first. Then press in hub. Push it in about 1/2" extra
Differential is a PITA, the front has to be raised fully into position for it to slide back far enough to get the bolts in. The jack alone won't do it due to the position it's pushing up at. I needed to block it up with wood to get one side high enough. Took me forever to figure out exactly what the problem was.

Problems
 

Bushing Fiasco
The energy bushings were sold to me on the premise that they have better heat resistance than the whitelines. However there is a problem with the geometry. Used as is, they would change the angle the differential sits in the vehicle. I ended up hack sawing and belt sanding them to size. I was to do it over, I would of left the OEM ones in. Also you need to reuse the center hub on the rear. Burn off the old rubber they say. Didn't like that part but I guess that's why this kit is cheaper.
Shaft Stub BS
Old stub w. threads, new stub w/o. WTF! Didn't notice this till I went to put the bolts in last night. Spent a bunch of time trying to pop it back out but it won't budge. Freaking banging on the stub sucks because you don't know what you're doing to the bearing inside. Going to buy bolts and nuts for it. What I wanted to do was chop the old one and put it back in. Problem with the bolts I could find is they are grade 10.9. The 76 ft lbs on the torque spec indicates these are grade 12.9 Can't find 12.9 anywhere. Moving forward with the 10.9s and going to drop the torque spec to 60ft-lbs. What BS! Been thinking about why...I'd bet it's not OEM and I'd bet it's made out of sub-standard material where the threads can't handle the proper torque. (Just guessing)

Update
 

Was planning to have this done last night (Monday). Fiddled with the differential mounting all evening instead.
Tonight for sure!

Good writeup. Something i plan on tackling in the near future.

Great thread!

Thanks guys! This would of been much easier if I didn't run into the problems I did. Hopefully I can save everyone that wants to do this a couple of headaches. I would be on the road today if it wasn't for the stub problem last night. Luckily Mr. Metric (local store) has what I need. Will-Call pickup today!
Finish tonight for sure. (famous last words)

Test Drive
 

So finally finished it! Figure with all the headaches, parts hunting and modifications, I've got about 24 hours into this project. I must be supper slow as I've seen some estimates as low as 8 hours. Did it alone so I'm sure that added some time. Oh yeah, test drive... First thing I did was take it to the biggest emptiest parking lot I knew of. It was about 6:00pm so I couldn't do anything fun but, I did the Cusco break-in procedure. 10 figure 8s. I know everyone who saw me though I was a moron or something. OS Giken says no break in required but I figured it couldn't hurt. If it made it better, great! No clicks bangs or funny noises whatsoever during the figure 8s. Cool, that's why I spent the extra $$$s. Next I wanted to find a spot to kick it out and see if it fixed the fishtail snap issue I've hated about the car. Did a u-turn, 1st gear pitch and held the peddle to the floor. Not too far, probably only 20 degrees but it pitched out and no snap back. Haven't done anything else yet but it looks like it's performing the way I hoping it would. Drove to work this morning with the radio off to see if I could hear any different tones but no change. The energy differential bushings must be the perfect hardness to provide stiffness and minimize noise. They might just be worth the hassle. The car did seem to go into VDC mode easier on one turn so I turned it off like usual. Need to leave it on and drive it a couple more days to see if this is real or not. So initial impressions... :tup: This car is slowly becoming bad-a$$. Waited 57.7k miles for this. Should of done it sooner but I didn't have the rear bushing excuse.

1st Oil Change
 

I put on about 800 miles on the LSD and did the first oil change. Quite a bit of metal shavings on the magnet and substantial amount fine particles suspended in the oil. The LSD is super grabby at slow speeds. If there's any leaves or gravel on the ground, you can hear the tires spin a little when pulling away from a parking spot. Hopefully this won't cause too much additional wear on the tires. Loving the way the car puts down power on corner exits now.

Z1 Differential Cover
 

Cool Picture of the Z1 Differential Cover Fins hanging down to catch air.

Great write-up! I'm probably going to be upgrading my Base LSD with the VLSD from the sport model. Is your list of necessary items updated?