Limited Slip Differential

Hi, does anyone have an opinion about this? One mechanic I spoke to
said it's highly probable that the grinding sound I hear for the first
couple of minutes of driving the car (the sound then dissipates after a
couple of minutes) means that the LSD needs to be replaced.

Another said it MIGHT need to be replaced, but changing the diff oil
might solve the problem.

We're talking about a 1989 Toyota Cressida, with about 120,000/miles.

Neither of the mechs actually physically inspected the diff, but they
both DO know my car rather well. I'm just not sure why one is so sure
it needs to be replaced. Maybe it's based on the expected lifespan of
this part?

Thanksya for any ideas.