i believe that the viscous pack from a 7" sierra diff can be unbolted from the crownwheel of an LSD diff and retro fitted to an 'open' non-lsd diff to make it an LSD (ie take a VC pack from a 3.62 diff to and fit to a 3.14 diff that was never offered as an LSD by Ford).

if thats the case, is it possible to remove the same VC pack from a 7" diff and add to a 7.5" open diff to create an LSD version?
i have an LSD 3.62 7" and an open 4.27 7.5" which i want to hybridise to create an LSD 7.5" diff with a 4.27 ratio.

Anyone know if its possible?

cheers CNH

7 and 7 1/2" can't be changed over. You will need a 7 1/2" lsd

ok thanks for that. So the VC pack is different too?

yes