Hi, mates.

Started custom axle for Jimny couple of weeks ago. Going to use Vitara rear third member. But GrandVitara case looks better (without A-arm mount) to me. Is it possible to fit large Vitara gears and diff case to GV third member case?

P.S. By some sort of strange things its my first post despite of being registered for seven years... 0__o

Moreover, there're plenty of 4.3 ratio gears in GV and almost none in older Vits. Just in diesel european cars.

...sorry, but I can't modify my first post don't know why. 8(

Which generation of Vitara & Grand Vitara are you asking about?  Second gen (98~05) GV centers are pretty much the same size as first gen (89~98) - you can fit the first gen rear center into the second gen axle, but not the other way around because the second gen center lacks the upper mount, needed on the first gen.

Which generation of Vitara & Grand Vitara are you asking about?  Second gen (98~05) GV centers are pretty much the same size as first gen (89~98) - you can fit the first gen rear center into the second gen axle, but not the other way around because the second gen center lacks the upper mount, needed on the first gen.

Vitara is the first gen (88-98) and GrandVitara is the second (98-05). 
They weren't produced at the same time as I know.

So I want to put first gen ring and pinion in second gen case.

I know they are equal in flanges to axle but not sure about inner dimensions. I only know GV diff is smaller and ring inner diameter is smaller (that's why Vit ARB locker won't fit?).

As far as I'm aware the first gen ring & pinion will fit the second gens, provided you match the ring gear bolt count which changed from 10 to 12 in 1992 - so pre 92 can't be used, post 92 should fit.