We've been making some headway on our G35 project and wanted to document some of the modifications we've done and do some quick write ups to hopefully save you guys a bit of time and headache!
Here is what the underside of your Z or G should look like roughly (Ours features an ISR Single GT exhaust, yours may be a bit different with a stock unit or different aftermarket piece).If you are getting ready to install a new aftermarket differential such as a Tomei, Kaaz, OS Giken, or Nismo, here is a rough guide on the steps it will take.
Taking a bit closer look at the diff you will see one rear mounting location on the top left (This is a 17mm nut), and each axle output flange is secured on by six 14mm bolts and nuts.
We started off by loosening the 14mm nuts and bolts holding the axle output flanges, you can generally get to about 4 or 5 of these with the car in the same position, but may need to rotate the axles to loosen the final bolts/nuts. (repeat this process on the driver side)
We then moved on to the differential input flange and loosened the 17mm nuts/bolts holding the driveshaft to the diff. Again, you may not be able to get to all of these nuts/bolts and may need to rotate the driveshaft. Also if you have a different aftermarket exhaust you may need to remove that prior to gaining access to remove these bolts.
Once the driveshaft nuts/bolts are removed we removed all the axle output shaft nuts/bolts and pulled the axles back and out of the output shafts.
Next we removed the mounting nuts for the sway bar brackets (14mm), there are 2 nuts per side, 1 as shown in each pictures and 1 on the back side of the bracket. By removing these you will allow the sway bar to droop and make removal of the diff a bit easier.
Also, they are not pictured, but when looking at the rear of the differential cover there will be a small sensor with a 12mm bolt on the driver and passenger side of the differential, remove these bolts and sensors and place the sensors up and out of the way.
Next we moved on to loosening the front differential mounting ear bolts (17mm) we took care to break the bolts loose but not remove them completely, this way we could move to the rear 17mm nut and loosen and remove it completely prior to removing the mounting ear hardware.
When removing the rear 17mm nut we found it best to use a deep well socket with no extension, as when a standard socket and short extension are used you can contact some of the rear chassis bracing.
Before removing the front mounting ear bolts we placed a transmission jack under the differential to support it, then removed both bolts, freeing the differential.
Now you'll just need to slowly work the differential down, slightly forward to free the stud from the subframe, and then lower it more and move it backwards to clear the sway bar and subframe.
Once you have the differential removed sit back, and marvel at the mechanical feat that you just achieved, and get ready to install your new differential in to your housing and repeat the entire process, in reverse!
17mm deep well socket
1/2" drive ratchet
3/8 drive ratchet (optional for 12mm socket, can use 12mm 1/2" drive if available)
large breaker bar
*This is a rough guide to give end users an idea of the tools and techniques required to remove their differential. As with all mechanical work, we recommend that it be done by a competent professional or hobbyist with the proper tools and safety equipment.