I'm trying to get my 68 Mustang on the road. The car has been sitting for 30+ years so I'm going thru the whole car replacing what seems to be worn or ravaged by time. I am a novice at this and also new to Mustangs. I am working on the rear end and have the brakes, axles, seals, etc. out and now am wondering if I should pull out the differential and if so, what should I look for? I have no clue. Thanks for any advise you can give me.