Why does rockauto show 2 sizes of axles

[TonyD]

I have a 2004 and I started hearing a noise coming from the rear and today we put it up on the lift and you can feel the vibration on the left side and I can see leakage from the seal. So I go on rockauto and they show 7.5 or 8.8. How can you tell is by the number of bolts in the diff cover? Thought they would all have 8.8s

[BAD MERC]

The 8.8 is the only axle in the Marauder. Not sure why they would list anything else.

[fastblackmerc]

8.8" is the OEM rear end in the Marauder.

[Joe Walsh]

LOL
7.5" under a 4,400 lb Marauder would've been a 'temporary' rearend.