Rear differental question please help

[2000GmcJimmy92]

So I'm about to do a rear differental fluid service, I have a 2000 gmc jimmy slt 4x4 4 door, and I cant find out what gear ring size I have. It's either 7.xx or an 8.xx. It determines the gasket I'm trying to replace and I don't want to buy the wrong cover and gasket. So my question is if someone knows which measurements it is please let me know it would greatly appreciated. Thank you!

 

[2000GmcJimmy92]

Of you guys are haven a hard time trying to understand what I'm trying to ask this is what I'm referring to, click the link and look at the first two items and read there discriptions that's what I'm stuck on.

http://www.1aauto.com/1A/differential-cover/GMC/S15Jimmy/-/-/2000

 

[Morbugs]

well there is only one way for sure - get under there and get at it, or you can try to trust the 'build code' in the glove box, that weird combination odd letters and numbers on that sticker in the glove box actually means something, each of those indicate what went into building your "whip" ....