that is exactly right. biggest one is the 9956-22-400, 24mm ID!
smallest is 6mm, 9956-20-600 in copper, 9956-40-600 in aluminum

 

I meant for like the whole car. Didn't know if this hardware example meant that all the various part codes on the car could be understood by looking at the number if you also had a key. Seems i misunderstood and read into it wrong

 

oh ok, so in the US Mazda has 3 types of part numbers. the normal ones, that start with the engine or chassis, FDxx-xx-xxx or N3G1-02-200 or something. the second is for locally sourced stuff like touch up paint and floor mats and stuff, 0000, quad zero.

the third is for bulk stuff and hardware, and most of the nuts and bolts and washers and stuff fall into this category. the crush washers are, topical for this thread and simple. the nuts and bolts come in a bunch of different types so they get more complex
the nuts and bolts kind of work the same, part number is in the usual format, 4 digits, 2 digits and then either 3 or 4 depending.
for a hardware/bulk item, they start with 99
so 99xx-xx-xxx
there are a ton of prefixes, so we'll skip that and go right to the sizing bit. Mazda uses mostly JIS standard fasteners, and for a given bolt diameter, the JIS spec gives you the thread and head size. if they use a bolt that isn't JIS spec, it tends to just have a normal part number. for a bolt the last 4 digits tell you the diameter and length, and then because its JIS standard, we know the thread pitch and wrench size.

so for example, 9983-10-612,
99 = hardware
831 = phillips counter sunk flat
06 = 6mm, and we know that a 6mm bolt is 1.0 thread
12 = 12mm long. this is the length of the threaded part.
and if that is it, its in the default plating, which is a gold zinc.

9983-10-612B is the same, but its black zinc plated.

another, 9979-40-612, the oil pan bolt
99 = hardware
794 = dog point bolt with a plain head, no washer
06 = 6mm
12 = 12mm
and no suffix means gold zinc.

9978-41-035,
99 = hardware
784 = plain head and plain tip
10 = 10mm, i think JIS is a 1.25, but don't quote me on that
and 35 is 35mm long
its a Miata cam bolt, but its also used on the Rotary bellhousing to engine

i'd have a longer post, but there are a TON of variations of bolts and they don't all follow the pattern as neatly as they should.

if there is interest i'm happy to do a Mazda part number decoding 101 thread, its really simple

 

That post was great. Very interesting, thank you.

Do you have a document that decodes the makeup of these 3 different types of part numbers? Similar to how you did below.

ie: What document taught you that 831 = phillips counter sunk flat?

Yes please and thank you!

And again, if there is any documentation you have on any of this that you can share, that would be super cool.

And sorry OP for the digression.

 

so far its just taking a known correct factory bolt/part and then looking it up in the parts catalog. Mazda might have a list on the wall or something, but we have to reverse engineer it

https://www.rx7club.com/3rd-gen-gene.../#post12501072

 

nmoffat…you’re likely no rookie, but maybe for others doing this the first time, the fill plugs are pipe thread. Let that and the Teflon do their thing and don’t be tempted to over-tighten. Seen it twice now on other’s cars where the plug was way too tight, risking going thru or splitting the case.

 

I use it only in the transmission. Since my engine is making around 420whp, I use a heavier diff oil.AMSOIL Diff Severe Gear 75W-110 2 qts.

 

I also chose the Eneos Transmission fluid GL-5 75w-90.

Very interesting about the Ford fluid though. Might have to give it a try

 

Back in the day redline was all anyone ever recommended. I don’t drive the FD as often as I used too but when I did the change, I noticed it took longer to get to temp and it felt way notchier. I wasn’t impressed.
At the time my daily was the Miata so it always ran the dealer fluid (which I think is the ford fluid). Never had any issues.
Now that Im able to do everything on my own, I decided to give Amsoil a shot. Both on my RX8 and FD. Smooth as butter. Regardless of temp.
The FD still requires a tiny bit of heat before you start to get heavy on the shifter but once you drive it for 2-3min’s, she’s good. No more notchiness or stiffness when you attempt to row gears.

 

Its is possible that some people actually prefer a notchy feel?

 

I should say, excessive notichiness. By default all our transmissions come with a certain amount of notchiness. Which is very welcomed. However, you don't want to feel syncro's getting mashed whenever you shift a gear. That's how it felt whenever I made a gear change in the FD. I also noticed this in the RX8 when I first took delivery of it. I made them change out all the fluids and for a tiny bit, the tranny was doing alright. However, after about 6 months or so, I started to notice alot more syncro mushing regardless of temps.
I switched over to the Amsoil and she's been buttery smooth. In all temp ranges (she's seen as low as -30C and as high as 48C during the last 3yrs of ownership..).
The FD has gotten alot better since the change as well. As mentioned, it'll be about 2-3min's of gentle driving to do the 1st to 2nd gear change without killing a syncro (our 1st to 2nd gear changes have always given us issues. Worse in the earlier cars..). But once you get a tiny bit of heat into her, the gear changes become buttery smooth. With the default notchiness intended.

 

Maybe, though I think when people use the term "notchy" as a positive they just mean a precise mechanical feel.

The notchiness I'm referring to almost feels like grinding, but not quite. It feels like the shifter sticks at various points throughout the travel rather than slotting in in a single smooth motion. It is normal for even the best transmissions to have a little bit of notchiness when cold, but I can feel it a bit too much in my FD transmission even when hot.

 

the FD has some dual cone synchros, so its possible that feeling is the one synchro and then the second

 

Update: I have been running the Ford/Motorcraft XT-M5-QS for about a week, before this was a fresh fill of Redline MT90 that had been in there for several months. This is on a stock 14k-mile car, so the transmission should be in good shape.

Now, the fluid has only been in there for less than 50 miles, and I expect it will continue to improve. Even so, the Ford fluid is an improvement over the Redline. The 1st to 2nd shift is still stiff when cold, but the fluid seems to warm up faster, and once warm, there is less notchiness than before.

Why shops still insist on using Redline when it is clearly not ideal (and possibly destructive) for these transmissions, I do not know. Overall, I'm really happy with the Ford fluid and would highly recommend it.

 

Conceptually for a stock transmission at 82k miles, would you still switch to the Ford fluid? Honestly my transmission history is pretty nill so may have less than 82k miles if it was replaced. Either way going to probably try out this Ford fluid.

 

Yes, I would use it in any good FD transmission. The reason I mentioned the mileage and the transmission condition is because fluid can do weird things with worn out transmissions, so the result may not have been the same with a worn unit. For example, I used Redline MT90 in an old Z32 box that I bought with a bad second gear synchro, and it actually fixed the problem. The same thing that fixes the synchro though, may not be good for a perfectly working transmission.

Like I said, this seems to be the only fluid that is specifically recommended for older GL4-spec transmissions, was formulated for an OEM to smooth shifting, has the lowest cold viscosity available, and has hundreds of positive testimonials. Granted I haven't tried many fluids, but I would be surprised if there was a smoother shifting one than this.

To be honest, I was skeptical that fluid even makes as big of a difference as it does... one would think that all GL-4 75W-90 synthetics would be basically the same. But I switched from Redline after not being satisfied with the shifting performance to this Ford fluid, and it is a noticeable improvement (and seems to be getting better the more mileage I put on it).

Curious to hear your impressions if you switch to it!

 

Just picked up an FD and have been having some slight issues getting into 5th as it likes to grind ever so slightly if I don't baby it into gear. I'm also not too fond of the notchiness shifting into any gear.
Not sure what fluid is in the transmission right now but I'm going to try out that Ford fluid and will post an update!

 

If it's a 93, this is a common problem in the 5th gear from my understanding.

Shift Select Spindle Upgrade

 

Early 93’s had a weak 5th synchro…not just the select spindle. Both were improved in later models…the synchro with better materials and select spindle was stiffened. Most of us long-time owners have replaced both long ago. Should still be a lot of info on it in the FAQS and archives. But no amount of magic gear oil will improve it.

Everyone has their own opinions on the best gear oil. It’s like beer..it can be trendy, open to personal taste and often rationalization.

 

NEO and don't use an aftermarket shifter

 

Oh man you are a life saver! As much as I wish the gear oil would fix this, what you're saying and what you had sent sounds like the exact issue I'm having; especially considering I have a 93.
Going to definitely look into getting that done or doing it in my garage if I can find a good enough write-up with photos haha.

 

Derk…understand that if you already have a “grind” it’s likely the synchro is already damaged and the select spindle isn’t going to fix that. It’s external and designed to make it harder to damage the synchro, but not keep it from grinding once damaged. I bought my car years ago with a “slight grind”. Except for some tarnish from the years since, this is what that synchro looked like when changed….




If you’re a diy wrencher it’s a doable job. Look thru the FAQs and archives for info.

 

I just read up a little on it and I do intend on replacing the synchro as well as the select spindle to prevent this issue from happening to the new synchro.
And glad to hear it's doable at home! I am a DIY wrencher coming from the E30 world but I'm just not looking forward to removing the transmission for this job 😔

 

taking the trans out of the FD is actually pretty easy, its easier than the front shifter bushing thing on an E30 that is for sure!

 

With a lift it’s < 45 minutes from car to bench..but then I’ve had a little practice over the years. Not sure it was mentioned in what you already read, but don’t forget to order the rear output/tail shaft seal (cheap). Also a great time to change the fuel filter while the trans is down.