how to tell 3 bolt from 4 bolt rear end?

[buRn-AWD]

i have a 90 GSX and know i'm supposed to have a 3 bolt rear end, but i'm not sure if the previous owner may have put a 4 bolt rear in. how can you tell by looking? is it that the diff. case has 3 or 4 bolts or what?

 

[ASZRAEL1266]

it is called the 3 bolt due to there being 3 bolts that attach the axel to the wheel. Just get down and look at the wheels and see how many bolts attach the axel to the car. Hope that helps