When will the Raiders get their money’s worth from Jon Gruden?

In the final minutes of this ghastly loss Sunday, there was no sign of that manic Chucky grin.

Jon Gruden simply put his head down in disbelief and rubbed a furrowed brow somewhere beneath a sweat-soaked visor. The Raiders fell to 0-3 with their 28-20 loss to the Miami Dolphins. And they did so with the same agonizing thud as their previous three defeats — hanging close early before unraveling when it mattered most.

Maybe the Raiders can borrow a closer from the A’s because, as it stands, this Oakland team is blowing leads at an alarming rate.

Can the $100 million coach put his finger on why?

“That’s just my responsibility to fix it,” Gruden said.

And he left it at that.

But the same Silver &…