FORD TRANSIT REAR DIFFERENTIAL.
The rear differential on most RWD transits can be overhauled with the pinion bearing & side bearings being replaced in situ left longer and once the tapered bearings collapse damage will caused to the crown wheel , pinion carrier or housing. The crown wheel pictured below ,we suspect fractured possibly due to a heavy load or metal fatigue resulting in extensive damage.
Cost to replace bearings only £450 + Vat
If hard part damage has occurred its POA