Unfortunately, the placement of the pressure release valve located on the rear differential carrier can easily be exposed to outside elements, such as mud, water, dust and road debris which can cause rust and clogging of the pressure release valve. During extended use, the pressure in the rear differential carrier can go above the intended 5PSI and build up higher pressure than the design intended in the rear differential. With no way to release the excess pressure to the atmosphere safely, the differential fluid seeps from the axle shafts. The loss of fluid can and will cause damage to the rear differential carrier. This occurrence does not cause any warning lights or give any indicator to the users. This was the first design oversight.

Second, in the rear differential carrier assembly ball bearings were used in the pinion instead of the more mechanically sturdy tapered roller bearing. I believe this decision was due to the ball bearing’s lower drag constant and cost. Using ball bearings can increase the fuel economy and lower the costs of manufacturing. These pinion ball bearings function as intended when there is sufficient differential fluid in the rear carrier assembly. Due to their fragile nature of the ball bearing, the lack of differential fluid can easily damage them irreversibly. Such failure is possible with tapered roller bearings as well; however, they are more resistant to the lack of oil compared to the ball bearings.

Combination of these design oversights damaged the rear carrier of my vehicle irreversibly. There is no indication of the rear differential carrier leaking fluid or damaging the bearing. As the user, its possible to hear the whining once the problem occurs. Unfortunately, the whining sound is a clear indicator that the rear differential assembly is damaged irreversibly. I was lucky enough to realize the problem before a catastrophic failure. The failure of the rear differential assembly would result in gears seizing up and locking of the rear wheels. There is no way to know when the rear differential assembly will seize up either. On highways speeds, this problem can create dangerous life threatening conditions to the occupants of the vehicle as well as the other motorists sharing the road.