I know with the early production, 2009 Dodge Ram 1500 SLT
The Warren Michigan Assembly Line omitted placing an Adhesive Patch on either Pinion Nut or shaft threads, it is basically is like Loctite Blue Thread Locker
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My 2009 Pinion backed off & was leaking, it was caught by the Service Center before any damage was done.
That repair was poorly done & it was leaking again, while it was leaking, it was in for a normal service, at the Express Lane.
Less than 500 miles later, i took the Ram back to the dealership & complained that just 2 days before, my Ram was in for service.
The repair shop inspected the noise & found the rear end had minimal fluid & most of the gears had got hot enough to turn BLUE
They had to rebuild the rear end.
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I asked the Express Lane office why they don't check the rear ends for fluid in the 40 point inspection.
They said that they check the rear differential by looking at the wheel bearings, during the brake pad inspection, both are done while the vehicle is up on the hoist & the wheels are still on.
By the way, my rear differential pumpkin has a Dipstick on it
The Manager did not care & did not apologize for my differential being damaged