I'm not sure but i think sinice the helicoil came out you probably have to have a new one put in. If you cant do it any machine shop should be able to do it. Some hear might have a trick up there sleeve and will pipe in and let you know.
Normally a helicoil has got a small pin on the bottom, that allows you to turn it in, with a special tool (not too special, it simple is a small pipe with a cut on the end) after turning it in, you must snap off the pin on the end. in the usermanual of the diffs i read something about sending them back to UE, if you had any problem with the helicoil. They can replace it with a new one.
Here in Holland i know that there is a V-coil kit available for about 25 dollars, that comes with 20 M3 coils and all the tools required..