Review on Yukon Gear C1 D30 STD Replacement Differential by Norman Costello

WARNING: The filler plug could slip through the cap and fall into the differential case (yes I did). You just have to screw it in until it goes in and offers some resistance, but it can never really be screwed in. This makes it a very poorly designed product indeed, but knowing this caveat I assume it will work fine. The picture shows a square countersunk filler plug that actually comes with a countersunk 14mm hex head. Aside from the poor design of the filler plug, it fitted my Dana 30 well in my '96 Jeep ZJ. We need to see if the plug falls out during use.