Poly Differential Bushings - Transmission whine?

[Thumper13]

Its normal. When I did that to mine I freaked out. It will subside a little bit as they get worn in. On the plus side, your shifter should feel awesome if you have newer engine mounts, too.

This ^^ is one of the best mods if you're on old worn out OEM motor mounts, it's amazing the difference this will make !! The mazdaspeed mounts are far superior to the poly or delrin for keeping the NVH down.

[—RuckkehrMiata—]

I don't want to bash a particular vendor, but a local friend found out not all diff bushing upgrades were created equal. Even if they are from a well known vendor, who did make things right with a replacement set. Claiming he got a lemon, and that they've had drifters not have the same damage.

I'd stick with energy suspension, simply because they give you a metal sleeve to go in the center of the diff bushing. Without it, you'll end up like my friend, wondering why he has a strange clunk, removing diff bushing to investigate and finding out they've been goatse'd.

They were Prothane bushings, and came with the metal cylinder for the bolt.

[—RuckkehrMiata—]

This ^^ is one of the best mods if you're on old worn out OEM motor mounts, it's amazing the difference this will make !! The mazdaspeed mounts are far superior to the poly or delrin for keeping the NVH down.

God does it feel wonderful now, the shift just seems to catch now. There is much less hesitation from gear to gear. When I finally get the motor mounts in (few months away, waiting until I pull the motor for a seal/gasket rebuild) I can't wait to feel it then!