99 Suburban 2500 help

[JeffK5]

What rear diffs it got?

It's a 2wd .

I've hunted around and I find people saying it could have a 9.5sf or 10.5ff ?

[carwash]

I would take a look at it. If it looks like a 10.5ff, it is.

JK man, sorry.

[KargoMaster]

My former 99 GMC was a crossover year, full sized SUVs seem to lag behind the normal full sizes for the crossover point... so I would say that it would probably still be "Old School" 9.5/10.5... I do believe it could be either... or AAM 10.5?? (overall, no clue)