Notice the extra washers and silicone on the spring-retainer-plate boltthat goes into the differential cover. The inside of the cover waswelded where the spring-retainer bolt went through. A bolt can easilypierce the minimal cast iron in the area. Welding cast iron can bedifficult and minor leakage after repair is common. The welded area willbe sandblasted and cleaned with alcohol before applying J-B Weld epoxy.