For those wondering about the marks on the gear surface, that's just where the coating has come off during the gear lapping process, as we need to do that to match the ring & pinion together.

Hey all,

Not sure where everyone else is at with their gear swaps..but I've put mine off since I got them in October so I could do this:
https://cimg7.ibsrv.net/gimg/www.mia...3b2f48d0c1.jpg
https://cimg4.ibsrv.net/gimg/www.mia...6624c38214.jpg


I am beyond excited, this weekend it might be installed under the car!

REM?

Prefer WPC over REM (due to tolerances), but still does the job :)

Yes, REM. Wonder how much material it removes?

On a new set of gears, it's acceptable, but on used/2nd hand gears, it removed too much material that we couldn't use the gears any longer :(

WPC doesn't remove any material

Will certainly take your word for it as you guys are in the business of making gears. The shop I have doing this work specializes in moto gp style race bikes. They do this process where ever they can inside the engine from transmission gears to valvetrain parts and see very noticeable power gains. This is, also, race bikes which are not expected to last 100,000 miles. Good thing your R+P is brand new, hope the torsen bits are not ill affected! I will certainly ask them why they do REM over WPC when I see them later this week. Thanks for that bit of knowledge

https://cimg2.ibsrv.net/gimg/www.mia...bfeffacef7.jpg

Mike,

I am about to build a rear end with your gears. Would I realize any performance benefits from having them treated?

When we do the surface treatments, it's not increase in performance/power that we generally care about, but rather, the decrease in NVH and increase in longevity (due to the decrease in friction)

For me, performance goes beyond power. Thermal/reliability/NVH all qualify.

is it worth it?

WPC for us, most definitely

We use it on all of our own & sponsored engine/transmission builds

Great, thanks. I will get quotes.

All done and I love it! It whines a fair amount around 50mph but didn't notice it at slower and didn't seem to be present doing 75. Only did a dozen or so miles so rar. The torsen works perfect even with the gears REM treated.
https://cimg7.ibsrv.net/gimg/www.mia...0367fcb1ac.jpg
https://cimg8.ibsrv.net/gimg/www.mia...732c55c140.jpg

Did you get any further with the idea of putting together an AZ6 frankenmission? I'm thinking about traveling down this path myself.

Wow they rem'ed the piss out of those things. We rem some stuff at work and never go that extreme, though we also DLC right after rem which I think requires some sort of glass beading after the rem for adhesion, but we never have edges blown over that much.

Hey all, for those of you who ordered this setup for a road going car, I have a fix for you!

Your speedo is going to be way off. Not sure how it applies to 5mt as I'm running MSM 6mt. Atkins rotary can set you up with an RX-7 (79-93) speed sensor housing and the keyway, and oil seal to run either a 19 or 20 tooth speedo gear. Hooked mine up tonight and the readings against GPS were near perfect.

got part #s by any chance?

https://cimg5.ibsrv.net/gimg/www.mia...06c16ea025.jpg

And for the gear:

M503-17-441 (20 tooth speego gear) will give you the correct cluster readout to with 0.5% with 195/50R15 or 215/45R15 rear tires. If you want to run 225/50R15 tires you need the 19 tooth gear (M502-17-441).

Out of curiosity, did you set the gears up or did you have someone do it for you?
I'm curious if you needed to get new pinion shims or were the gears close enough for the factory pinion shim.

If you had someone set it up for you, who did it and what did they charge? I'm looking for a decent shop and you're only a couple hours away from me.

Also thinking about picking up a set of these. Is there still a fair number left?

How many people have run them this season? Any issues or comments?

(I have seen about the minor whine; Not a major major issue as mine is a streetible track car with poly diff bushings/awd engine mounts and a 3" exhaust that just beats track limits.)

Hello, just joined the page, I have been a stalker on here for a long time...
Anyways, just received my 3.307 gears from mFactory, I am sending the diff off for the install I will be sure to post pictures
I will try to give a full review and will post pictures and everything else.
Here are pics I have taken of the gearset I received. (Pardon bad phone pics!)
Gears are going into a 2004 MSM Diff.
https://cimg6.ibsrv.net/gimg/www.mia...deaa5ad6d0.jpg
https://cimg5.ibsrv.net/gimg/www.mia...715607bbcc.jpg
https://cimg2.ibsrv.net/gimg/www.mia...b8cc0dca85.jpg
https://cimg0.ibsrv.net/gimg/www.mia...74ba023d53.jpg
https://cimg1.ibsrv.net/gimg/www.mia...7d46225381.jpg
https://cimg3.ibsrv.net/gimg/www.mia...a09bf71d94.jpg
https://cimg4.ibsrv.net/gimg/www.mia...1f42c711cc.jpg

I ended up doing my own install so we'll see how that goes. Everything seemed to go pretty smoothly. Runout was good, dead on for most of the gear with one spot at .001". Backlash I got to max .0045ish, min .0033 or so. I initially checked everything with the original pinion shim but the pattern was a little too much toward the outside for my liking. Went about .008 thicker and the pattern seems to be much more centered on the drive side. Coast side was always centered regardless of shim. Here's a pic of the 2 patterns for comparison. (top=new, bottom=original)
https://cimg4.ibsrv.net/gimg/www.mia...57ef9a7f43.jpg

https://cimg3.ibsrv.net/gimg/www.mia...6ae7cc5d24.jpg

I went thru the gears with the back end up on stands. Seemed quiet until 6th gear and then I started to hear the slightest whine but this is also totally unloaded so I imagine it'll get louder to some extent. I will say, setting up a diff is tedious for a first timer.

Yeah, I just do not have skills, tools, or time to do it myself, I would be scared to mess up the gears and then be out the money if the gearset dies:rofl:
I'll be keeping what is going on my end on here, and will post videos somewhere of the diff whine, if there is any present. Let us know how yours works when it is in the car:skid:

I've finally had a chance to drive the car a couple times. Some regular street cruising and a few hard pulls to 60-70. No sustained higher speeds yet. So far so good though. Not really any noise to speak of. 6 speed now feels just like my 5 speed with 4:10s.

Miata Diff Info
 

So my diff should be arriving today, would it be okay if I were to start a new thread with all the info that is available?

Just drove with mfactory 3.3 for the first time. Makes all sorts of noise on decel. Solid diff mounts too. Also have a weird turbine noise when decel under 15mph

Anyone else with jet engine noise?

^ video?

Soon. Keeps raining around here

Starting my install today, hoping to have it done by tomorrow 😂

Heres a video of the whistle sound. Its only at low speeds when slowing down

And heres one of the decel noise. Does anyone know if this is a normal loud or an unhealthy loud?

Normal for those gears.

Yikes! I thought the Quaife gearset was noisy. That would drive me bonkers.

It is a fraction of the volume of the whine from a Quaife under power or in cruise. Any volume from the radio, any sort of exhaust drone, etc. drowns it out completely. It is really only audible under decel.

Fair enough, Andrew. Hard to tell ultimate volume from a cell phone video. Maybe inconsistent noises are more annoying to me - as a for-instance, the sporadic tire sizzle from RE-71Rs is a big turn-off for a daily driver. With my old Quaife gearset, gear noise was more constant and, to me, acceptable (although I still wore ear plugs any time I was on the highway).

I roll my eyes at whoever gave me a neg-cat for what was a fairly innocuous comment.

Yeah its only on decel. Thanks for the reply.

I dont mind it as my car is already stupid on the nvh scale but i just wanted to make sure it wasn't chewing all the teeth off or something.

Feels so nice to have actual gears now. And cruising in 5th and 6th feels like a normal car now

Diff is finally in!
 

Finally got everything installed currently have about 200 miles on the gearset, noise is definitely there, but not too bad mainly on acceleration, I'll make a video of the noise and post it in the near future. Cruising, it's not there, and with the radio on, the whine completely fades away... Anyways, ended up having Ben Herne AKA puddymod do the install, works great the new gearing is amazing, having 6th on the highway is very nice, like said about, it's just like a 5 speed with a 4.1 in terms of feel, and 6 is nice on the highway... I'll post a more detailed review once everything is finally broken in and I can get some video.

Did you remove the pinion damper? I found removing that, combined with going from void fillers to actual poly mounts added a fair amount of decel whine to the 3.6 gear.

^ Have any of you had REM or WPC treatment to the gearset? I am planning to have that done and I am wondering if it will reduce noise such as mentioned here or if it will only reduce wear / increase service life..?

Based on my personal experience with these gear sets, it will not reduce noise. The machining and finishing process used by Mfactory results in a less than smooth gear face. We have their 6th gear and ring and pinion in our FR-S. It's noisy too. The 3.3 in our NB, also very noisy but it was an early production run that did not get finished the way the rest of their gears do. It was WPC treated but had no effect whatsoever.

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.