Persistent Diff Whine

Hey guys, I'm back (Full disclosure I don't own a tacoma but the third member in my car is near identical to a tacoma's in design).

Had a diff whine that occured while coasting (deceleration), opened it up, replaced shot pinion bearing, put it all back together, and the whine, while quieter, was still present.
I probably torqued the pinion nut a little too hard, but it's a solid spacer, not a crush collar, so it shouldn't have mattered all that much.
Bearing I replaced the old one with was near identical to the one that went bad, down to the part number.
Pressed out pinion shaft again (a few days ago), and confirmed that the spacer was the same dimensions as a new part (57.72mm). Signs of heat on its top, but nothing obviously damaged (heat was probably from friction of failed bearing not spinning properly while pressed against spacer)
Not sure what else could be bad with the bearing. I didn't lubricate the new one before putting it in, and just thought the diff fluid would do the trick. Was that my mistake? Any help would be greatly appreciated, have been stumped by this issue for 8-ish months now.
Thanks,
Dom

 

Many Tacos have a unique dif whine under coasting or light acceleration conditions. Both my '06 Taco and my current '21 Taco exhibit the same whine.

 

Yeah, but it isn't a Tacoma, and it didn't have a whine before hand. That's why I'm trying to fix it.

 

Out of curiosity what is the car (make/model/year) that you're chasing this on? I'd get the related service manual and try to set it up per that vehicles specs.

If you look through the forum, you'll see that even those who re-geared to a different ratio still have the whine (sometimes worse than stock). This is after allegedly professional shops doing the work. I don't think anyone on here has been able to solve the diff whine feature Tacos come with.

 

It's a 1995 Mitsubishi Pajero Mini, a JDM kei 4x4. It has a third member, albite smaller than a taco's.