Underdog said:
I recently installed an ARB in my Dana 30. After one week ( about 200 road miles)I pulled the diff to check the oil and noticed their metal flakes in the oil and a lot of metal particles on the magnetic plug. I used "royal purple" and the diff cassing was throughly cleaned when installed. The back lash was set within specs and there was no new wear patterns on the gear teeth (used same gears). I cleand the diff again and replaced the oil and plan to pull it again this weekend, is this normal for an ARB?
You did not mention if you set the pre load correctly. The two settings that are the most important when replacing the carrier are the backlash (should be set to exactly what it was before unless out of specs) and the pre load on the carrier bearings. This usually around .005” to .010” more than o end play. If you installed all new bearings the pre load on the pinion is also critical. I am assuming you used the same gear set. If you did and re used the same pinion shims there is little need to check pattern. If you did not change the pinion bearings then there is no need to check pattern as long as the back lash was set to where is was since the pinion shims are what determine pattern.
Just a hint, If you did change out the ring and pinion set. Just add or subtract the shim thickness engraved into the end of the new pinion which what is on the old pinion plus the original shim pack. The by the book procedure is complicated and requires a special tool set to determine the shim pack. Otherwise it is very time consuming and tedious to set the correct pinion depth. You also need a lot of experience reading patterns to it right.
I am factory trained as well as an instructor myself to set up differentials. I just tried to simplify it for you. If you have metal in there now I would recommend replacing all the bearings at the very least. The ARB O rings and seals will not live long if there is any metal particles left.
Todd
