Hi every one
I want to swap my AT differential to MT differential to fix the 4.01 final gear
but the problem is the AT differential drive shaft flang has 3 bolt flang and the MT differential has 4 bolt flang
can I swap the flang ?

 

yup. Theres lots of threads on here many with great pictures on the different flanges and pumpkins and whats involved in pumpkin swaps.

Usually people aren't changing the gears too (at least not themselves as they don't have the spacers/measuring equipment) so they have to deal with the issue of setting the tension on the crusher collar from the outside which may make changing the flange slightly tricky, but if you are going to be putting in bigger gears too then you might as well use the AT pinion and flange and put in a new crush collar at that point...it'll be the least complicated part of the swap and the parts don't cost much.