I have a 1972 Dodge Demon with a 340-4 speed. It has an 8.75 rear
end with a sure grip with 4:56 gears. It is a 489 case. The rear end is
making a clunking noise when I get on the car and when I back off the
car.The u-joints are fine.I can drive the car and under normal driving,
it is fine.When i jump on it,it sounds like the rear universal is going to
come through the floor board or the pinion is slamming forward. The gears
were installed two years ago.I do have a driveshaft loop.It will be coming
out friday.Sure-grip problem or maybe excessive backlash.Sure-grip has
never been rebuilt.The rear end is coming out friday.I pulled the axles.
They are fine.They are Moser axles with green bearings.I value your
input.