Heavy duty differential cover

[Yamafan]

How does one tell if he has a heavy duty or other aftermarket cover for the rear differential? Mine appears to be newer (less rust) than the rest of the differential and by the amount of silicone oozing out of the joint it is obvious it has been apart at one point in its life. The only ID on it is PAT 278 570

Thanks

 

[SwaveDave]

Theres a picture of the heavy duty one that can take 6 tons of pressure , in Jegs Catalogue. Maybe compare it to whats on your diff. Im going to get one next time i need diff. work done.

Dave