Ratio's are the same the number of splines are NOT.

The 90 will be 10 spline,

and the disco 24 spline,

You need the whole axle or new half shafts if you intend on just swapping the diffs if you swap the whole axle then you need the disco front radius arms because they are ever so slightly wider backs are the same.
 
Cheers guys, I have a Front and Back axle from a 300. however the front Axle of my 1986 defender 90 believe it or not is cleaner than the R reg 300 one. So what's the best way to go about putting the defender 90 one on the front and the 300 one on the back ? ( sorry im new to all this )
 
The 90 axles being older are made of better I believe thicker and better quality steel than the disco ones.

I personally would keep the front 10 spline defender axle simply because the CV's are much stronger than the disco ones and you can fit your 24 spline diffs IF you get hd front shafts. making the front end pressty strong.

Rear yea 24 spline has disk brakes I would be looking at radius arm mounts make sure theyre solid some can be quite badly rusted through.
 

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