91Chevy S-10 10 bolt Rear end limited slip swap trouble???

I just took my rear end apart in my 91 Chevy s-10, to change it from a 1 legger, to a limited slip. any how I bought the rear limited slip gear off a neighbor for a 10 bolt gm rear end, I was told it came out of a newer jimmy from 2nd or 3rd gen. not exactly sure what year, any how it fits in my rear end fine, but when I went to put my axle shafts back in they didn't fit the spline inside the spider gears from the 2nd/ 3rd gen limited slip to the axle spline from my 1st gen s-10 so my axles where spinning inside the spider gears, my question is does anyone know how many different rear axle splines there were between the generations and if this is even possible???

P.s. both have a 3.42 ring gear

I started doin some research, and found out, my original axle shafts were 26 spline, and the new rear gear are 28 spline limited slip unit, now I know that much, I have a buddy with a 4.3L rear end, and I was going to check it out & get it off him, but now the question I have is in LMC Truck new axles are sold, for both 26/ 28 spline, but the 26 are meant for a7 1/2 ring gear, and the 28 is for the 7 5/8 ring gear my question is can that 1/8"(1/16" on each half) make that much of a difference if i run my original 3.42 ring gear that went with my 26 spline axle shafts on the factory 28 spline limited slip unit quote un quote with the 7 5/8 ring gear??? or should i just build up the 4.3L rear end if it has the 28 spline shafts? the reason I ask is cuz I was told the ring gear and pinion must stay together as one because of the precision machining, This is only for my 2.8L with a t5 thats built up, so im really not interested in swapping the rear end to anything bigger yet... im trying to save gas and not one leg, so im keeping the highway gear... thanx anyone that can help...  

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