I have a fleet of Cat 725 ADT's, a few months ago I had to change the front differential on my AFX01320 machine. It was completely destroyed it looked like something had come apart inside and done the damage. Sourced a good running takeout and installed and put the truck back to work. Within 2 hours operator reported that when he went to engage 6x6 only the front and rear axles were getting drive. Pulled the drain plug and you guessed it metal fragments came out with the oil. Have pulled and stripped axle, ALL of the ring gear bolts were laying in the bottom of the housing, the ring gear was just floating on the shaft. There is absolutely NO damage to any component in the differential. ALL of the bolts are perfectly in tact and unmarked, it is as if they all backed out when not in use and ended up at the bottom of the housing. As a mechanic I can't get my head around why? Why no loctite on bolts? Why no damage? Why caterpillar are saying that it is impossible for this to happen. Also, if this is what happened on the front will it happen on the rear and if this is what caused the front to fail do I go after CAT for the loss of the front? Truck only has 6000 hrs. Thoughts please.
There was a problem with the dowels walking out in the diffs and the owner on the truck would have received a letter stating there is an update and it would be taken care of. This was in 2007. Scheduled oil samples would have caught this before it totally failed with iron over 150ppm and copper over 70ppm. This update was never done to AFX1320. As for the ring gear bolts, i have seen a few backed out while performing the dowel update. They now use longer bolts with spacer so they hold the torque. I always use blue loctite in a diff.
Thanks for the info I will bring it to the attention of the manufacturer when they come to inspect the differential tomorrow. I will check the dowels tomorrow but all 28 bolts were backed out and laying in the case.