To start with, all of these parts swap into any 84-89 300ZX, there are always questions about the differential. Let me make this crystal clear: ALL Z31 half-shafts spline in to the differential in exactly the same way, hence that are all compatible with the LSD. The ONLY exception to this is 88SS halfshafts and the 88SS Viscous LSD, but if you have those you might as well make a killing selling it on ebay to someone. Anyway, all R200 differentials (except the viscous) will bolt right in. The only problem you could run into is the companion flange for the driveshaft (this is the front flange on the diff itself), it may need to be swapped from your existing diff. Locating a LSD for a Z31 can be tricky, as many many 70-89 Z car owners want one and they were only available in the 4/87-89 300ZX Turbo or from Nissan Motorsports directly. I highly recommend finding one in good condition, as they are rather costly to rebuild (the friction plates and discs alone cost $180). If you can find a whole 4/87-89T car for a reasonable price and you have room to tear it apart, it is ABSOLUTELY the best option.
You can usually identify the LSD version of the R200 by the finned rear cover. They normally go for $400-$600 or more used in good condition. The brand new Nissan Motorsports units go for about $800. That said, the diff is fairly easy to install.
Begin by breaking loose the 4 main bolts that hold the differential to the cross-member, then remove the sheet metal guard between the diff and the gas tank. Next, drain the fluid. Loosen the 4 bolts that mount the diff isolator/mount to the car (not the two holding it to the diff), then unbolt the driveshaft (instructions in Haynes manual), remove the half-shafts (at least the drivers side) and carefully remove the differential, remember it is quite heavy!
If needed, swap the companion flange from your other differential. Just remove the retaining nut by putting some strong bolts through the holes in the flange to keep it fron turning. Gently tap the flange off in a circular motion around the flange's circumference, tap the new on on in the same way and secure it with the nut.
What the 88T's diff looked like when I pulled it out.
I've been told by a few driveline shops specifically to NOT use synthetic in clutch type LSD's and be sure to use a friction modifier designed for metal-to-metal plates. What it looked like after I cleaned it up, repainted it and re-sealed the rear cover:
I did this swap with the rear end out, but you can also do it very easily without removing much at all. For your entertainment, this is what the rear suspension looks like outside of the car:
The simple process to changins the diff goes like this: Drain gear oil and pop both half shaft splines free of the diff. Uunbolt the differential from the driveshaft, remove the 4 long bolts holding it to the rear crossmember, the two nuts and two studs holding the differential mount to the car itself. Remove the right rear half shaft (easiest to unbolt rear shock stay to access flange bolts), pop the drivers side free and slide the diff down and out at angle. Be very careful not to drop it, the housings are very heavy and you could seriously injure yourself. Re-installation is the reverse of removal:
