Poly Differential Bushings - Transmission whine?

[—RuckkehrMiata—]

I just had a garage put in my poly diff bushings for me, and now I am noticing a whine that is the same frequency (or some harmonic) of my motor whenever it happens. It is subtle, and kind of throaty, but not like an exhaust rattle. Happens more while slowing down in gear. Have you ever experienced this? Is it expected/normal? This is my DD so if it is something damaging my car I should know before my next commute ._.

And so I don't open another thread:

Question 2: Where can I get new/rebuilt Axles for a 92?
Looking for online/community guys

Thanks all!

[Thumper13]

I put in poly diff bushings and haven't noticed any noises that I didn't have before I installed mine.

There are plenty of used parts guys around.. Treasure Coast down in Pt St Lucie area and on line Planet Miata just to pick 2 names. New axles...how about Rosenthal's Finish Line ?

[— kung fu jesus —]

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.

[SM16RMSM]

I figure I will hear some more driveline noise when I do my bushings. New axles, good luck. You can find a few places that will make a rebuilt axle but since your in Orlando, look up Redline Auto Sport in Kissimmee. Estaban has good used axles in stock. If I had a 1.6L, I would have upgraded the 1.6 diff to the torsen 1.8 diff.

[—RuckkehrMiata—]

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.

A friend told me "Did you consider it is just the poly's conducting sound better?" and made me kinda think for a minute, but att the same time I got worried about possibly having damaged something in the install. Motor mounts are happening before too long, but not yet
I am gonna be doing the mazdaspeed ones tho

[— Agent☣Orange —]

I put in poly diff bushings and haven't noticed any noises that I didn't have before I installed mine.

That's because you're deaf and decrepit, you mouth breather.

[—RuckkehrMiata—]

That's because you're deaf and decrepit, you mouth breather.

[—RuckkehrMiata—]

I figure I will hear some more driveline noise when I do my bushings. New axles, good luck. You can find a few places that will make a rebuilt axle but since your in Orlando, look up Redline Auto Sport in Kissimmee. Estaban has good used axles in stock. If I had a 1.6L, I would have upgraded the 1.6 diff to the torsen 1.8 diff.

I did some listening while driving at low speeds, and it sounds like it is just the new harder bushings conducting differential noise into the body. The sound is growing on me, hah!
Thanks for the reference, I have been to their site a few times but never looked any deeper. I would consider upgrading the diff, but it is a very low priority item right now since I need to go through and replace all my gaskets/seals on the motor and put a new radiator in. It is going to need doing in the future if I ever have the money to spring for boost.

[Bummer]

Naturally, you'll have increased vibration transfer. Did you remove the PFF from the trans end? I assume you did. May need to check alignment.

[Thumper13]

That's because you're deaf and decrepit, you mouth breather.

Up Yours......I'm NOT a mouth breather.........the other two,well,ok.

[—RuckkehrMiata—]

Naturally, you'll have increased vibration transfer. Did you remove the PFF from the trans end? I assume you did. May need to check alignment.

I pretty much imagined it being diff whine directed directly into the cars body, acting as a speaker heh.
I did not do the install myself, as I do not have the tools. I can't say I know what you mean by PFF (today I will learn?).
Alignment is definitely out, but on the front end from hitting a hidden raised cross walk in a 45 (who the hell does that?)

[bigx5murf]

Normal, goes away in time.

[—RuckkehrMiata—]

Normal, goes away in time.

Thats what I have figured out from here so far. My concern was that the mechanic put everything back together properly, I didn't want to get 100 miles down the road and find my diff was demolished or something.

[Bummer]

I pretty much imagined it being diff whine directed directly into the cars body, acting as a speaker heh.
I did not do the install myself, as I do not have the tools. I can't say I know what you mean by PFF (today I will learn?).
Alignment is definitely out, but on the front end from hitting a hidden raised cross walk in a 45 (who the hell does that?)

It might have made more sense had I actually written "PPF". Power Plant Frame. You know, that big chunk of railroad track connecting the trans to the diff. They're supposed to be set at a certain dimension from a certain plane... Being out of align can cause some noise. I've always just made sure the bolts were back in the same place in the slot they came out of. Hopefully, like the others have said, the noise will just go away.

[bigx5murf]

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.