Axle internal swaps

Hi all!

I'm doing a chassis swap on my 1986 90 and since the rear axle was rotten as a peach swapping that as well. A previous owner had fitted a 300tdi so I assume the axle thats in it now came from the same disco donor as its disc not original drum. I acquired a good solid replacement axle from a later defender missing the internals. My question is what if anything do I need to swap?

THe axle housing itself looks the same but the outer ends are slightly different - stub axles & discs slightly different? The shafts feel as if they are located happily (flange bolts are a different pitch though) so can I just bolt them in?

how later a defender

No idea to be honest

300 tdi 90 and disco axles are basically the same, any pics of both

Having trouble loading pic. Basically on old axle flange bolts look like af fine. Slight curve on flange face and lock nuts sit further forward. New axle look like metric flange bolts flat face on flange mount alightly diffetent casting on hub assembly and discs look bigger. Measuring the hub sections they seem same and axle sits flush on flange on both so i assume theyre ok