Broken Diff
As stated, a cap may have broken allowing the ring gear to move away from the pinion and the rest is history! I am using a 8 3/4 in a Dart Sport but only for one more go round! When it breaks...and it will, a Dana will be installed. ALSO your trans needs to come apart! DO NOT RUN THIS CAR UNTIL YOU CHECK THE ROLLER CLUTCH! Bad things happen to the trans case/legs/ankels etc. if you do not check the trans! If you don't believe me google 727 trans explosions! Pix will help you decide what you should do! I'm sure someone in the forum has pix to pass along to you!