90 Miata Transmission Upgrade(s)/Rebuild - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Suspension, Brakes, Drivetrain discuss the wondrous effects of boost and your miata...

Reply
 
 
 
LinkBack Thread Tools Search this Thread
Old 06-30-2015, 05:14 PM   #1
Newb
Thread Starter
 
Join Date: Jun 2015
Posts: 15
Total Cats: 0
Default 90 Miata Transmission Upgrade(s)/Rebuild

Hey everyone, picked up a $40 5 Speed with the shift **** sawed off at the turret ball. I've rebuilt transmissions from a variety of makes and models.

I must say the internals are some of the most frustrating with the many C-Clips and Roll pins. Not to mention the large nuts and long shafts..

Anyhow the transmission in the car is doing all right. Got some noise on overrun, that quieted up after the change to Torco MTF. It has not gotten worse, but will need replaced in the future.

I have reviewed the parts diagrams on Jim Ellis Honda, and have saved copies of the gear shafts and forks for the years 91, 93, 94, 97, 99; and for the most part they look the same, apart from the turret changing. Also, I have reviewed the parts list at AdvancedAutosport from Dave as well as a few other threads and sites.

I have also come across the TSB regarding fixing the 2nd Gear, sleeve, hub, and synchro on these older units, as well as an updated unit in the 94+. These hub/sleeve/synchro are different part numbers despite everything else connected to it having the same part number, including the shafts and shift forks. Why is the TSB for the 90-93 call for a different assembly than 94+? Can I use the 94+ in the 90? Differences? This is what makes me confused.

Along with this there also is a TSB for the shift change lever, A>B>C without a clear explanation for what changed. This adds to list of potential parts to pick up from Mazda, unfortunately not from MazdaSpeed, maybe I will have to go to a few AutoX to sign up, if the transmission lasts.

It seems that in addition to the standard Bearing, Synchro, and Seals, I plan to upgrade this as far as possible while it is open. I have heard talk of shift forks being updated by Mazda several times, but lack the recent part number, or adequate description. Is it on the interlock side or the hub side?

In addition, I plan to replace the reverse sensor, the 5-R rod, all the C-clips, roll pins, springs, copper washers, nuts, other damaged parts during rebuild.

I was hoping the collective minds on here could help me devise a list of current parts that can be used to upgrade even the oldest transmissions to the best condition.

Thank you

Last edited by TurboSled; 06-30-2015 at 06:11 PM.
TurboSled is offline   Reply With Quote
Old 06-30-2015, 05:18 PM   #2
Elite Member
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,461
Total Cats: 782
Default

A 6spd out of a 99-05 would be a great upgrade.
concealer404 is online now   Reply With Quote
Old 06-30-2015, 06:07 PM   #3
Newb
Thread Starter
 
Join Date: Jun 2015
Posts: 15
Total Cats: 0
Default

I understand the benefits of upgrading to a superior model, however I do not have the money for a new 6-speed transmission, but look to restore what I have to like-new at a reduced cost.

I also enjoy the challenge and learning process with each new transmission I repair. Gain tools and knowledge. Perhaps down the road I will pick up a used 6-speed to rebuild, but have heard from various sources they are notably more difficult, and starting off with the simpler variant.

I have read a copy of the enthusiast manual explaining the procedure to tear down and rebuild, I also have replacement bearings and seals. I plan on deburring all the gear engagement teeth and sliders when its apart, as well as a few other tricks..

Thanks
TurboSled is offline   Reply With Quote
Old 06-30-2015, 10:52 PM   #4
Goin Innnnn!!!
iTrader: (7)
 
Chooofoojoo's Avatar
 
Join Date: May 2014
Location: Denver, Co.
Posts: 460
Total Cats: 40
Default

I paid $300 for my used 6-speed. Had ~60k km on it. Shifts like a greased unicorn, no rebuild necessary.

While the price I paid is atypical of current prices, there are good deals around. Just keep a look out.
Chooofoojoo is offline   Reply With Quote
Old 07-01-2015, 10:11 AM   #5
Elite Member
iTrader: (5)
 
m2cupcar's Avatar
 
Join Date: Jan 2005
Location: Atlanta
Posts: 7,237
Total Cats: 290
Default

Quote:
Originally Posted by TurboSled View Post
...the large nuts and long shafts..
Welcome to miataturbo
m2cupcar is online now   Reply With Quote
Old 07-05-2015, 06:35 PM   #6
Newb
Thread Starter
 
Join Date: Jun 2015
Posts: 15
Total Cats: 0
Default

Bump for serious discussion. I tried to lighten it up to make the read less dull. I figure many of the avid enthusiasts have worked their way to the turbo world and then this site.

I am more that willing to post links to resources I've been looking at studying this application. From many forums such as Grassroots Motorsports, Spec Miata etc, but could not create multiple threads on all of them.

It seems like you guys break them rather often, and fail to see they will eventually run out as predecessors have. I find enjoyment in restoring and upgrading cars rather than the quick gratification achieved from scrapping and swapping in another used unit. If anyone can help point me to a more technical forum or knowledgeable user, that'd be great. It seems there is always a Tranny guru or two in each community. I'm hoping to replace any known problematic pieces, such as the 2nd gear assembly, but lack complete understanding of the revisions.

Thanks again
TurboSled is offline   Reply With Quote
Old 07-06-2015, 10:28 AM   #7
Elite Member
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,461
Total Cats: 782
Default

I honestly don't think i've ever even heard of anyone trying to do this. Once someone breaks enough 5 speeds, they jump to a 6spd or a Quaife.
concealer404 is online now   Reply With Quote
Old 07-06-2015, 10:38 AM   #8
Supporting Vendor
iTrader: (1)
 
OGRacing's Avatar
 
Join Date: May 2014
Posts: 1,764
Total Cats: 46
Default

I'm very surprised nobody has made dog box gears for a miata trans.
OGRacing is offline   Reply With Quote
Old 07-06-2015, 10:42 AM   #9
Elite Member
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,461
Total Cats: 782
Default

Quote:
Originally Posted by OGRacing View Post
I'm very surprised nobody has made dog box gears for a miata trans.

99.9% sure they're out there. Open your wallet. And your anus.
concealer404 is online now   Reply With Quote
Old 07-06-2015, 11:41 AM   #10
Supporting Vendor
iTrader: (1)
 
OGRacing's Avatar
 
Join Date: May 2014
Posts: 1,764
Total Cats: 46
Default

Quote:
Originally Posted by concealer404 View Post
99.9% sure they're out there. Open your wallet. And your anus.
a quick google search says in the 14k range. That is also surprising. as i can find a t56 dog box gears for 10k.
OGRacing is offline   Reply With Quote
Old 07-07-2015, 06:29 PM   #11
Newb
Thread Starter
 
Join Date: Jun 2015
Posts: 15
Total Cats: 0
Default

C'mon lets stay on on topic, I am not interested in a Dog box, 6 speed, quaife, used swap box.

Are you guys telling me that the Subie, Honda, Chevy and others have better build/repair capabilities? You are generally a minority, but you have MazdaSpeed..

Just looking for some people knowledgeable about the 5 speed boxes and their revisions.

It appears according to the exploded views that the updated 2nd gear assembly and synchro is interchangeable. They ride on the same shafts, and use the same shift forks and rods.

I actually believe you could even take a new turret off, and slide it onto the old transmission, and have it work with the remodeled tailshaft/shift lever assembly..

I just wanted to reiterate, I got this working 5 speed for $40. And you all are using them as consumables. But I bet you if I shoved this transmission away for 10 years under a tarp, I'm gonna have no problem ridding it for $400, even if I didn't monkey with it. What other investments do this. I have a collection of STD crankshafts from desireable cars worth stupid money, all bought for under $100 apiece. I've watched it happen over and over with different model cars.

I like the manual transmission! And I think you all do too. It is a great possibility they will stop being produced by common auto manufactures in the futures. Something to think about.

Turns out, my girlfriend drives the miata, and I bought this as a learning exercise for her. It can go back together the way it came, rebuilt, but seeing as I've done this a few times, including a few straight cut boxes, and like to challenge myself so I don't become old and negligent. Her car is a B package 91, stock as hell. Modified NGK wires, Plugs, 94.5 Type 1 Torsen LSD, 1.8 Driveshaft, $110 Carquest Axles (Fingers Crossed), MazdaComp Engine Mounts, ES RSB Bushings, ES Diff bushings, CNC Skou/DIY reroute. Fixed the stock audio with a Kenwood Deck, Polk 3.5(4) 6.5(2) Speakers, Blaupunkt 50x4 RMS amp and rewire it all 14G as per Jeff Anderson. We got the hard top and a new glass soft top. 15x8-9 6UL 225 RS3v2. The car is fun.

I'll let this thread cook a little longer, see what it comes up with. If nothing, Ill come back

Last edited by TurboSled; 07-07-2015 at 06:40 PM.
TurboSled is offline   Reply With Quote
Old 07-07-2015, 06:35 PM   #12
Elite Member
iTrader: (3)
 
concealer404's Avatar
 
Join Date: Aug 2011
Posts: 8,461
Total Cats: 782
Default

I keep forgetting you can't delete posts entirely on this site.
concealer404 is online now   Reply With Quote
Old 07-07-2015, 09:09 PM   #13
Newb
Thread Starter
 
Join Date: Jun 2015
Posts: 15
Total Cats: 0
Default

No need to delete anything,

1994 - 1997 Changes:
Added a Shift Rod Interlock Pin (R501 17 351)
Upgraded 3rd-4th Shift Rod (M504 17 421A)
Upgraded 2nd gear Synchro (R504 17 26Y)

2nd Gear

I was not however able to locate the first 2 updates on a parts diagram, and suspect they may be incorrect or out dated. Im about to contact Mazdaspeed request information, but wonder if they will provide support not being a member.

The 2nd gear synchro seems to go on the same PN hub and sleeve, and are reflected in the attached gear pics.

I currently have the "C" revision and wonder the difference with a "Y" seems to defy the revision patterns. Curious if it's worth getting the other.

Part Number Description Quantity Interchangeability
New Old
M502 17 265C M502 17 265B 2nd Synchronizer Ring 1 New -> Old
M503 17 262A M503 17 262 1-2 Clutch Hub Sleeve 1 New -> Old
M505 17 260B M505 17 260A 1-2 Clutch Hub Set 1 New -> Old

Source: http://www.miata.net/garage/tsb/s004_92.html

Notice it calls for the C synch,

Also, even in the 94 diagram with the Y synch, it still calls for the old hub.
Confirming my suspicion that the diagrams are inaccurate. Can anyone share the MazdaSpeed ones?

Change Lever - >
M524 17 510C Change Lever

^Change Notes?

Source: http://www.miata.net/garage/tsb/sb005_93.html

5-R Fix
M506-17-431A reverse rod
M506-17-640A Switch


Source: http://www.miata.net/garage/stuckreverse.html

3-4 Shift Rod/Others
Maybe I will be able to find the shift mechanism change in 3-4 as well.

Thanks

Credits/Motivation:
Miata Transmission Changes 1990-2005 - MX-5 Miata Forum
Jimellis Honda
Attached Thumbnails
90 Miata Transmission Upgrade(s)/Rebuild-91-shafts.jpg   90 Miata Transmission Upgrade(s)/Rebuild-94-gears.jpg  

Last edited by TurboSled; 07-07-2015 at 09:23 PM.
TurboSled is offline   Reply With Quote
Old 07-07-2015, 09:54 PM   #14
Supporting Vendor
iTrader: (31)
 
Savington's Avatar
 
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 14,362
Total Cats: 1,323
Default

The reason you can't find any information here about the 5-speed is because we break them in ways that cannot be fixed. There's minimal interest in tweaks to shift forks or synchros when all the teeth come off every single gear at ~250wtq.
Savington is offline   Reply With Quote
Old 07-08-2015, 04:01 AM   #15
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 17,992
Total Cats: 1,458
Default

Miata owners are cheap as ****. I bet 99% of the people on this site would ever consider spending 10k on gears, let alone 14k. Especially when it becomes more economical to v8 swap when you get above 6 speed breaking power levels.
aidandj is offline   Reply With Quote
Old 07-17-2015, 01:25 PM   #16
Newb
Thread Starter
 
Join Date: Jun 2015
Posts: 15
Total Cats: 0
Default

I do not believe that they will always break, especially after a refurbishment with new bearings holding the gears securely in place.

Wear is loose, and loose gears have play, or lash. As that lash doubles the force of it slamming x4. I bet almost all of you have 5 speeds with wear and very few have used a rebuilt one based off the attitude on here.

The conditions at which a 5 speed breaks is largely variable on transmission starting conditions, driving style, and engine configuration, etc. Saying something is rated for a specific HP or TQ is asinine in my experience, and hardly every concrete. That being said, I don't plan to ever venture above 250wtq, and enjoy the 5 speeds.


You're right, most people on here do not have thousands for a tranny, possibly because they wasted it all being foolish.

Learn to polish a turd rather than scoff at the idea and you might be worth something more than what is in your pocket. Do the turbo guys just buy their way through the journey, rather than learning like the N/A guys?

I dont see more than $400 going into this thing, or why this contribution/venture is any less significant than others. Post count? You guys post count club? This could help a lot of people out. I know you guys love talking about dicks and **** but thats about only universal thing I've found on this site. Embracing the gay-aura I suppose. Cool for you guys.

Ok, so I might not be able to find information here, which is disappointing. Can anyone recommend alternative sources, forum or people?
TurboSled is offline   Reply With Quote
Old 07-17-2015, 01:44 PM   #17
Moderator
iTrader: (11)
 
sixshooter's Avatar
 
Join Date: Nov 2008
Location: Tampa, Florida
Posts: 15,664
Total Cats: 1,560
Default

For informational purposes, our 5-speeds contain many of the same internal parts as the 5-speeds in the 1st generation RX-7. Perhaps that will be of use to you.
sixshooter is online now   Reply With Quote
Old 07-17-2015, 02:54 PM   #18
mkturbo.com
iTrader: (24)
 
shuiend's Avatar
 
Join Date: May 2006
Location: Charleston SC
Posts: 13,775
Total Cats: 1,106
Default

Quote:
Originally Posted by TurboSled View Post
I do not believe that they will always break, especially after a refurbishment with new bearings holding the gears securely in place.
I have a friend who races spec miata. His mechanic rebuilds 5 speeds for him, refreshing almost everything in them. I have seen those rebuilt 5 speeds break within a season of use multiple times. You may not believe that the 5 speed's are week, but after 10 years playing with miata's I have seen a ton break, and not ever seen anything that would fix them from breaking again. So go ahead and spend a ton of time and money refreshing the 5 speed. Maybe it won't break on you, maybe it will, but overall we collectively have enough experience to know it is a waste of time and energy.
shuiend is offline   Reply With Quote
Old 07-17-2015, 05:32 PM   #19
Boost Pope
iTrader: (8)
 
Joe Perez's Avatar
 
Join Date: Sep 2005
Location: Chicago (Over two miles from Wrigley Field. Fuck the Cubs. Fuck them in their smarmy goat-hole.)
Posts: 26,317
Total Cats: 1,914
Default

To reinforce what's been said already, here's what a 5-speed gearbox typically looks like once we're done with it:



That ain't gonna be fixed. Which is why we consider transmissions to be in about the same category as brake pads once you get to a certain power level- it's a disposable wear item.



Several years ago, Flyin' Miata worked with Quaife to put together an upgraded set of gears for the 5-speed box. The raw gearset sold for $2,700 and they offered an assembled transmission for $4,000 on an exchange basis (+ $450 core charge).

Miata owners being the chronic cheapskates that we are, everyone whined that it was too expensive, and FM quietly discontinued the product a few years later due to low sales volume and claims that it "did not live up to expectations."


Also note that while the 6-speed gearboxes are a tad stronger, they are, rather annoyingly, geared even shorted in 6th than a 5 speed is in 5th. This means that RPMs will be higher at a given speed after installing a 6-speed gearbox unless you also swap out the diff (or R&P gears) for a taller set. (The 6-speed cars came with 3.909 rear gears, as opposed to 4.30 or 4.11 in the 5 speed cars. To really take advantage of a 6 speed in a high-torque car, you need to expend some shoe leather and track down one of the unicorn 3.636 sets.)
Attached Thumbnails
90 Miata Transmission Upgrade(s)/Rebuild-img_2629.jpg  
Joe Perez is offline   Reply With Quote
Old 07-17-2015, 09:25 PM   #20
Elite Member
 
codrus's Avatar
 
Join Date: Mar 2007
Location: Santa Clara, CA
Posts: 3,877
Total Cats: 344
Default

Quote:
Originally Posted by Joe Perez View Post
To really take advantage of a 6 speed in a high-torque car, you need to expend some shoe leather and track down one of the unicorn 3.636 sets.)
3.636s aren't unicorns, they're readily available from Mazdaspeed. They're just expensive ($550 plus another $100 for the VSS plus $250 for setup because you probably don't have the tools to DIY it).

3.3s are unicorns, as in rumored to exist but nobody has ever seen one.

--Ian
codrus is online now   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
3rd Time's a Charm...hopefully. zephyrusaurai Meet and Greet 2 09-28-2015 11:59 PM
VR6 to Miata Swap ScrapinMX5 Meet and Greet 8 09-28-2015 02:04 PM
Another Alternator thread ihiryu General Miata Chat 9 09-28-2015 11:22 AM
Koni 1150 Coilover Kit drumman83 Suspension, Brakes, Drivetrain 2 09-25-2015 08:03 PM
starting issue Johnny Tater Engine Performance 3 09-23-2015 07:10 PM


Tags
5spd, 5spd makes great dildo, ban hammer cometh!, handle, know-it-all moron, rebuild, ssp-11, the butthurt is deep, turd polishing, update

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 01:05 PM.