Pinion damper?
 

On my differential I've noticed the damper thing that's located on the end of the pinion is starting to separate and rotate. I'm not sure of the exact name, but it's the piece on the pinion that's located directly behind where the bolts to connect the driveshaft go. Mine has been slowly moving over the past 6 months, but I don't really put any miles on the car. Another local friend is having the same issue except it's completely separated and rotating freely.

What's the purpose of this part? Is it necessary to have on there? The 1.6 cars don't seem to have one. Why is it this is happening? If it's not needed, any ideas on how to remove it without having to get the diff setup again?

i nvr noticed a damper on that. there are just flanges on our US spec cars.

There is a damper. It is a 4-flanged rubber one that sits just behind the flange.

I thought the one on my car was rubber, but I need to verify that. The one on Ben's car and the one on his spare diff is metal on the outside with a rubber inner section.

They're only on 1.8's, it's obviously to help dampen something. Whether it's dampening drive shaft vibrations from the differential or vise verse, I have no idea but Mazda added it with the 7" ring. Is it separable from the pinion output shaft? Definitely something you should look into replacing. At least that's what my friend Cpt. Obvious is saying.

i dont remember one on my 96 diff is all maybe i didnt look correctly. though hmm time to crawl under the car once more and check.

Ran across this doing a search and bringing it back to life.

These are only on 1.8L manual trans cars. Auto/non torsen do no have them. I wil post if/when I found out just how necessary they are.

They are metal with a rubber isolater similar to a harmonic balancer. The isolater deteriorates and the weight comes loose...makes a nasty rattling sound.

I may just go w/o...