may be a silly question but do escort cossy rear diffs fit on to a 3 door cossy and are there any differances?

 

4x4 diffs are 7 inch items,whereas 2wd diffs are 7.5 inch jobbies,dont think they are interchangeable,could be wrong though. think 2wd is a bit stronger.

 

yeah, 4x4 diff is smaller, both internally and externally - the mounting in the 4x4 beam is consequently smaller too, so 2wd diff won't fit in a 4x4 beam AFAIK. (conversely, 2wd beam mounting is too big for 4x4 diff)
As said, 2wd diff is stronger than 4x4 too.

 

As above