Hey I have an 89 S13 and i plan on installing my Tomei LSD bymyself and if i have to set backlash how do i do it? thx 
is it a gear set or full pumpkin?
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i know this may sound noobish but what do you mean by full pumpkin sorry
This is by far the best write up i have seen for an LSD
http://www.driftfactory.com/lsdinstall.php.
Basicly as long as the gears are meshing properly you don’t have to change anything, just be very careful not to mix up the shims.
thanks for all the help guys Edit: The link doesnt work :huh:
then go here
look down on your right near the bottom of the page under installs
Click on KAAZ lsd
Read
Win
^Word. I used that to help me with my install a couple weeks ago, covers everything nicely. I think Tomei’s got it spot on with their diffs though, just install the ring gear and put the shims in exactly like they were and the gears should mesh just fine.
Don’t forget to pick up some Permatex Prussian Blue to check the gear pattern though. It’s a coloured dye that you apply to a few teeth, rotate the gear a couple of turns and it will show you how everything’s meshing.
Oh, and don’t use synthetic gear oil in the diff. Tomei diffs don’t like it.
B-Wurm 
**Edit: From he FSM
fixed link http://www.driftfactory.com/lsdinstall.php