Diff fluid

[Greasymechtech]

I made him aware that the truck specs 10W30 and 5W40, he could care less as he the gets the oil for free in 5 gallon buckets.

He he could care less about the engine oil, then why care about the differential? Use whatever grade/type he can get for free.

I avoid working on and giving advice to clueless owners, especially friends/family.

I understand that you're the mechanic to the friend. So, he gets to blame you for the future issues with the engine, transmission, xfercase, and diffs.
For certain customers/family/friends, use the OE fluid. Anything else puts you at fault. I'd use a 75w140 but this is the type of customer, that could care less, that you should refill with Mopar 75w85.

Thread size and hex head/socket size are different. Not even sure why its confusion. And yes, I would not torque a 8mm thread to 30 ftlbs, unless the diff and bolts were made of some fancy unobtainium. My 18mm threads(24mm socket to prevent confusion) are torqued to 30ftlbs in my vehicle's diff and xfercase. 8mm at that torque.... I'd expect it to break too if it didn't simply strip.

 

[BrianF]

I guess I should have stayed in the engineering field all these years so I could take part in this thread. My bad. Perhaps I should only discuss issues pertaining to my current profession. Again, my bad. Perhaps we can continue the virtue signaling?