MFactory Gearset Update
 

Just throwing this in here, I've had the gear set for about 5000 miles and it's been working very well, but as noted above it does whine, in my car up until 60mph... It's not super loud, having the radio on drowns it out.... I previously tried to record a video of the whine in the car and i couldn't hear it over the exhaust... To answer your question, I didn't not treat my gearset in anyway

Yeah I had mine polished up like jewelry and it still whines. Same as above, between like 30 and 60 its noisy but higher speeds either the road noise drowns it out or it just goes away. Still love it though!

Gear fluid?
 

I've read the last few pages of posts.
Regarding the whine for the 3.3, I see no mention of what kind of gear fluid anyone is using. Do different brand fluids make a difference in noise? I'm considering getting a OS Giken. As I understand it, I'm stuck with what they provide. Unless that's just they're way of selling expensive fluid.

I'm assuming this is for a manual cable?

I'm wondering if one of these gears could be modified to fit on a NB speed sensor. If so, That could be an easy and cheap fix.

In case anyone is interested, I have this gearset in my car and I have some footage which gives somewhat of an idea what the gears sound like.
I installed these myself with basic tools and a dial indicator.
In this footage, I have a microphone inside the trunk against the floorboard so the audio will be a bit exaggerated. The whine really isn't bad at all.

Finally installed mine. I did it myself with a dial indicator and 7" micrometer. I had my gears WPC'd.

I replaced all the bearings/seals/crush sleeve with mazda parts.

I have a slight whine below 20mph on decel, have not had it over 70mph yet. It is way better than I expected from that perspective.

Jim Ellis parts list for speedo, installed.and functional, but not yet verified for accuracy

https://cimg7.ibsrv.net/gimg/www.mia...7cf4656d19.jpg

Thanks Ted. Please update when you verify speedo accuracy. I'll be doing mine soon.

Reminds me of that straight cut gear whine in the old JRSCs. Kinda like it :)

Reporting back

Speedo accuracy is good according to the speed check signs we have in the area.

These gears are money. I am really liking this modification.

Can anyone here confirm that Mike or any official representative of MFactory made contact to initiate a recall of the "prototype" gearset?

Can anyone out there verify what the 'recall' was for? Was it because the gear didn't have the right cut and created a pattern that lived up at the high side (crown) of the tooth? I am having a lot of trouble adjusting the pinion height to move the pattern down to the face of the gear. It lives along the crown and doesn't want to move down as I increase the spacer thickness.

I'll grab a photo and post in a second.

The surface finish on the original gears was terrible. Machine marks everywhere.

Would post a pic, but the pic I had must pre-date this phone.

Drive Side. This is the best I've been able to get it. Most of the others are slid way up the face. This pattern covers about half the face and is definitely off.

https://cimg0.ibsrv.net/gimg/www.mia...3ac93912bb.jpg

So I'm still in the middle of this install. For you folks who did the install themselves, did you find that you had to increase your pinion spacer by a lot? Like, 6-8 increments higher spacing. I'm looking at an original spacer of 3.14mm and it doesn't move the pattern down the face until I get to like 3.34mm.

UPDATE: I'm seeing what may be my problem - the OEM spec of 7.3003-7.3031" measured on the bearing caps is a bad way to do it with used parts. Setting it to 7.300" is causing a ton of slop in the carrier bearings. NO preload on those bearings is making it impossible get a consistent result. And, if I were to assemble all of this I'd just end up with a loose ring bearing and it would quickly destroy itself.

Any inputs would be appreciated.

I had to add also. Went from a 4.1 MSM to this set. Mine is still on my bench and I need to pull it back apart as I just put it together with the old bearings to test fit everything before I press the new bearing on my pinion shaft. I'll see if I can confirm what I added tomorrow. I'm also putting in the Weir solid spacer on mine. Pattern and back lash all measured up good. One thing I did run into was first time I assembled it all was my back lash did vary more than I'd like so I marked the high/low spot on the gear and on the outside of the diff itself, pulled my ring gear back off the diff, clocked it, reassembled and that seemed to get it damn near dead on all the way around. Not sure if that is normal at all but it worked well for me. I figured there is some tolerance in the ring and some in the diff so by clocking it to the best spot I seemed to get the best result. Pain in the butt but worth it in long run.

I swapped my diff to an OS Giken with new bearings pressed on it so can't comment on the carrier bearing issue. Mine seems good at the OEM spec. My car is also pretty much stripped so it won't be tested for quite some time...…..

Are you willing to share your pattern on the drive side? Sounds like we are at the exact same point in the build.

I have pretty good backlash all the way around so I didn't need to clock.

Can anyone with diff experience chime in about why Mazda doesn't do carrier (ring gear) pre load? Example: Toyota 4runner needs a 150-200ft/lb turn on the thread rings (tons of preload). I also read that "you really can't have too much preload on the carrier."

I might still do some adjustment to mine but this is what I've got at the moment. Had it together/apart a couple times while I was off work and maybe not quite as good as I had it earlier. Looks a bit faint in the pics but seems fairly centered heel/toe and back lash seems good. Open to any feedback on it.

Pro tip - Don't leave gear marking paint on your ring and pinion for about a year while you get distracted working on other projects. It does eventually start to dry and is a pain to remove. I guess it is called paint...…..

https://cimg2.ibsrv.net/gimg/www.mia...597f8f1585.jpg

Your pattern looks nearly identical to mine. Only difference is that I still have a dark area at the top of the tooth that indicates that I'm still too high.

I also have the dark line down at the bottom. This concerns me because I read it as a spot where the pinion gear (top land) is contacting more directly than the rest of the face. Perhaps this is where the gear whine comes from. And perhaps this would wear down with time and go away.

I'm going to try more 'shims' (I'm using aluminum foil) to bring that pattern further down the face.

You need to use carbon steel shims. Aluminum will compress under load and wreck your clearances. Shim In A Can is easy to find in a variety of thicknesses, typically you can get it at a bearing shop (Whisler Bearing down in CoSpgs is where I've gotten it...they have a location in Denver metro IIRC).
Too much preload is definitely a thing. The bearings will eat themselves alive if they are overly tight, or conversely if too loose they will hammer themselves apart.
Are you freewheeling the carrier while you create the contact patch, or loading it down? It needs loading (resistance) to get an accurate reading, so that the pinion is doing at least a small amount of work while it is rotating and pushing against the ring. Your pattern will not be correct if unloaded.
Are you reading the coasting side, too? What does it look like? Less important if the R&P are brand new, but can offer some insight.
This page has a very good pattern troubleshooting section about halfway down (nothing in the spec section is relevant). Even if you think you have it all on lock take a look anyway: https://www.differentials.com/techni...-instructions/ I might have posted it early on in this thread, but here it is again anyway.

If all else fails, and you don't want to risk it getting wrecked, take it down to Jacks Transmissions in CoSpgs. They have set up tons of diffs for high performance applications, and are MFactory distributors.