My 03 G35 sedan was suffering from a worn out rear bushing and some very annoying peg leg burnouts inherent to the open diff. Since replacing the rear bushing requires dropping the diff, I figured that it was time to go LSD. I picked up a complete used viscous diff from an 05 350z for about $160 and purchased a Prothane diff bushing set for it.

Despite what everything I have read and the FSM stated, I did not remove or disconnect the swaybar or any exhaust parts, nor did I drop the subframe. It is tight but totally possible to do the swap without doing so.

As far as cutting out the stock rear bushing, I just used the drill and cut method to get it out.
Now, I apologize if this has been covered before but so far, I have not seen a writeup on a sedan poly bushing install.
To begin, the sedan has the stupid spare tire well pushing right up to the the back of the rear subframe, making it impossible to press in the new bushing from the rear as the instructions state. The Prothane rear bushing is only chamfered on one side and it is directional so I had to get creative. I had to press it in from the front, requiring that I chamfer the other side of the outside edge of the bushing to get it squeezed in.
I did not take any pics of the bushing while out, but here it is after I pressed it in with a 7" threaded rod and some 4" steel plates:
my prothane chamfering job

Getting the original open diff out was not too hard because gravity assisted me but getting the new one in was a little tough. Here is how I positioned everything before I lifted the new diff in.






I used a floor jack to position it and lift it into place, which sucked. On the bright side, the swaybar helped hold up the front of the diff while I positioned it to bolt it in.



I found that I had not pressed in the metal insert from the old bushing far enough into the new bushing so I could not get the two front bolts in. I was able to force them into alignment by wrapping ratcheting tiedows around the diff output shafts and pulling it rearwards, anchored on the rear tow point.

Once I got the bolts in, I torqued up everything according to FSM specs and did some off the ground drive and reverse testing to make sure I didn't screw it up.


After a fluid change and some highway and twisty testing, I am happy to say that a Nissan viscous lsd is a major improvement! I was concerned that a whole new diff would cause driveshaft and axle vibrations but it was perfectly smooth. The car launches much better in a curve and can do some more entertaining maneuvers while driving

Sorry that I do not have more pics but I would be happy to clear up any questions/omissions.

Oh and if you are interested in cost breakdown, I spent:
$160 - Complete Diff/Carrier Assembly
$42 - Prothane Bushing Kit
$24 - 2 qts (1.5 used) 75w90 Valvoline Synthetic gear oil
$6 - threaded rod, nuts, washers, hardware, plates
=
$232 total swap cost

 

I'm so glad that I live in the state where they never salt the roads during winter.
I just did a diff swap on my coupe and seeing your pix with everything rusted makes the work on my car is that much enjoyable

 

I am jealous. Rust is the primary reason that I did not remove any exhaust parts or the swaybar. Every friggen bolt gets rusted in place on this car!