I have a 1990 V2500 Suburban. It has the 10 bolt GM front axle and I am led to believe that it would have the 30 spline inner shaft ? Is this correct ? It is 4:10 gear Ratio. I have a random intermittent popping sound/clunk when running in 4wd. I believe I have narrowed it down to the right ( passenger side ) It only does this in 4wd with both manual hubs locked. with the right hub unlocked and the transfer case in gear either 4hi or 4lo the noise /popping does not happen. I have had the manual hub apart and it is fine and works as it should. I suspect either something with the axle shaft or internal in the differential. This clunk/bang occurs very randomly and does not involve turning. Any Ideas before I tear into it ?