Yes, both axles will have the same ratio. Otherwise, it would bind and not move in 4wd....have to match.
I pulled front axle off of a 89' 3/4 ton suburban...was a 10 bolt (Dana 44 equiv). I'm guessing you will have a Dana 44, but who knows!
Maybe you get lucky!
I'd say you have NP208 transfer case.
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- Jeff
89' K5 Blazer, 2.5" lift, 35" tires
04' GMC Yukon XL, 3/4 ton, 8.1L