Hi. My 94 C4 has a leak in the Diff. My mechanic said it was from the fill plug. So he removed it and put a thread seal compound on it. It stopped for about a month then started leaking again. I was looking for a new Dana 44 fill plug but they are hard to find. Does anyone know an alternative?

Diff plugs are not known to leak. I would be suspicious of possibly a crack in the cover, or something wrong with the threads in either the plug or the cover. Not sure what the thread pitch/size is on that one off-hand, but a replacement should be available. I can check and see if I may have one somewhere.