About 4 months ago I pulled my OPDA & did a modified FOGMod using an oil cup instead of a grease zerk. My gear was worn very unevenly & I planned on replacing it with a Crown gear at that time but 4 Wheel Parts was out of stock. I now have pulled it again to install the gear & see how the oil mod is working. I have only a little over 1600 miles so it won’t qualify for a long term test.
As has been reported, the Crown gear has the (single) hole located in a little different position. I also found it to be too tight to slide onto the shaft more than a very small amount. I “honed” the gear a little be wrapping a strip of emery cloth around the shank of a Phillips head screwdriver & rotating the gear. After several test fits I had it going on snugly. After lining it up with the hole in the shaft I drilled through that hole (using it as a guide) & through the other side of the gear on my drill press. With the gear installed, I measured the end play & found it to be 0.062” Thanks to TJJP77’s help, I tapped the wheel down to where I now have 0.026” endplay.
I learned something interesting doing the Crown gear install. I didn’t find the gear to be particularly hard since it “honed” out fairly easily but what was interesting was that as I first tried to install the gear (pre-honing) just by hand, twisting it slightly as I pushed inward I realized it would not make it & I reversed course. When I got the gear off, I could clearly see that the gear was galling the shaft! How soft is that shaft if hand turning will leave scoring lines? No wonder we get shaft scoring all the time. Like I said, I don’t consider the gear to be that hard but it seems that it is harder than the shaft.
As far as the oil mod itself, there is no apparent further damage to the shaft/top bushing. Granted it is only 1600 miles. Some oil has accumulated inside the OPDA housing which tells me oil is making it to the top of the bushing & over.
I added a little reinforcement to the oil cup assembly & attached it with a small bolt through the existing hole in the housing. That has had a second benefit of keeping the accumulated oil from spilling out.