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-   -   5 speed carnage (https://www.miataturbo.net/media-53/5-speed-carnage-39231/)

bryanlow 09-17-2009 03:01 AM

5 speed carnage
 
So I took apart my busted 5 speed:
http://lh3.ggpht.com/_RVtFpHgZITY/Sr...2/IMG_0027.JPG
Here are the guts:
http://lh6.ggpht.com/_RVtFpHgZITY/Sr...2/IMG_0017.JPG
Where'd 3rd gear go?
http://lh6.ggpht.com/_RVtFpHgZITY/Sr...2/IMG_0021.JPG
Here it is!
http://lh6.ggpht.com/_RVtFpHgZITY/Sr...2/IMG_0020.JPG
What sucks is the syncros in this transmission are in perfect shape and it used to shift perfectly. The new (to me) one doesn't shift quite as nicely.

This is kinda cool:
http://lh5.ggpht.com/_RVtFpHgZITY/Sr...2/IMG_0023.JPG
It's kind of a trough that collects oil and feeds the driveshaft bearing here:
http://lh3.ggpht.com/_RVtFpHgZITY/Sr...2/IMG_0026.JPG

Damnit I need a 6 speed.

FRT_Fun 09-17-2009 03:20 AM

Wow that is brutal. I'm scared for my trans now :|

18psi 09-17-2009 03:23 AM

This is exactly why I shift my car slow like a pussy

Savington 09-17-2009 04:10 AM

Did it free-rev in 3rd? My tranny acted the same in 3rd as it did in neutral after I toasted it - I could put it in 3rd, let the clutch out, and get out of the car, and it wouldn't go anywhere. :bang:

icantthink4155 09-17-2009 10:42 AM


Originally Posted by bryanlow (Post 455019)
Here are the guts:
http://lh6.ggpht.com/_RVtFpHgZITY/Sr...2/IMG_0017.JPG
Where'd 3rd gear go?

I know nothing about transmissions, could someone take this pic and label 1st, 2nd, 4th, 5th, and reverse?

Is it not possible to just swap the 3rd gears out?

levnubhin 09-17-2009 10:48 AM

I'm betting my 3rd gear is going to look like that soon.
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curly 09-17-2009 12:40 PM

It is possible to swap gears, and replace broken ones. But unless it's a qualfie set, it's just going to break again. It looks like Mazda used a pretty steep helix angle to get rid of noise, if I'm not mistaken that's part of the reason the gears aren't terribly strong. That amd material I'm guessing.

tyson87 09-17-2009 01:07 PM


Originally Posted by levnubhin (Post 455119)
I'm betting my 3rd gear is going to look like that soon.

ur a bitch, after i pass on teh 6spd u say some shit like this...

cueball1 09-17-2009 01:07 PM

So who here's gunna try sourcing a tougher gear set to swap in that doesn't cost 3k like Queef?

Joe Perez 09-17-2009 01:50 PM


Originally Posted by icantthink4155 (Post 455115)
I know nothing about transmissions, could someone take this pic and label 1st, 2nd, 4th, 5th, and reverse?

Here:

http://img39.imagefra.me/img/img39/2...pm_ab78008.png

The main gear is always engaged on both the main shaft and the countershaft. The division between the input and output halves of the main shaft is just after (above) the main gear. All countergears are continuously engaged on the countershaft.

The main gear drives the countershaft, and the four countergears continuously drive their mating gears on the main shaft. To select 1, 2, 3, or 5, the appropriate output gear is locked to the main output shaft, with the other output gears freewheeling.

There is no 4'th gear per se. As 4'th is 1:1, to achieve that ratio, the input shaft and the output shaft are simply locked together, and the countershaft freewheels all of the main gears.

Reverse is similar, but with one additional gear in the lineup- the reverse countergear drives an idler gear, and then the idler gear drives the reverse main output gear.

curly 09-17-2009 02:49 PM

I've said before, 3k for a transmission gear set from qualfie is very reasonable. Keep in mind a ring/pinion set is not terribly precise aside from a ground bore. Theyre a meshed set, meaning the more you run it, the more the pinion grinds into the ring. You can see from Joe perez's recent write up about his new gear set that the lathe grooves are still visible. Look up the price for a ring pinion gear set from a reputable gear company like qualfie, and times it by the six (I think reverse is included) gears you get with a transmission set, and add in the money to make the gears somewere near a quality class 12, and you should be somewhere near their price. Kudos to whoever prooves me wrong and makes a cheaper set, but I'd be incredibly surpised if it were possible.

bryanlow 09-17-2009 04:10 PM


Originally Posted by Savington (Post 455036)
Did it free-rev in 3rd? My tranny acted the same in 3rd as it did in neutral after I toasted it - I could put it in 3rd, let the clutch out, and get out of the car, and it wouldn't go anywhere. :bang:

Yep, mine did the same.


Originally Posted by icantthink4155 (Post 455115)
Is it not possible to just swap the 3rd gears out?

Yes it is, and until I get a 6 speed I'm keeping this gearset as a spare. Hopefully I blow up 2nd gear next time.


Originally Posted by Joe Perez (Post 455218)
Here:

http://img39.imagefra.me/img/img39/2...pm_ab78008.png

There is no 4'th gear per se. As 4'th is 1:1, to achieve that ratio, the input shaft and the output shaft are simply locked together, and the countershaft freewheels all of the main gears.

:bowdown::bowdown::bowdown::bowdown::bowdown:
Joe, you're badass. I was wondering where 4th gear was.

r808 09-17-2009 06:12 PM


Originally Posted by Joe Perez (Post 455218)
. . .There is no 4'th gear per se. As 4'th is 1:1, to achieve that ratio, the input shaft and the output shaft are simply locked together, and the countershaft freewheels all of the main gears.

I'd like to add that this is why when people blow the input shaft, the only gear available to them is 4th. The power is not actually being transmitted through gear teeth because the input and output shafts are directly coupled on the main shaft.

wayne_curr 09-17-2009 06:21 PM

Additional information:
HowStuffWorks "How Manual Transmissions Work"

There is a manual transmission simulator in that article that lets you switch gears and watch what happens in the transmission.

orion4096 11-12-2011 09:43 AM

Old thread, but does anyone still have Joe's picture of the 5speed with the labeled gears? If so, can you post it or send it to me?

Opti 11-18-2011 12:08 AM

Would it be impossible to just source some straight cut gears from another transmission that are the same size.

curly 11-18-2011 12:48 AM

No OEM gears will either fit, be strong enough, or are straight cut. Or any combination of the three.

Miater 11-18-2011 03:46 PM

Has anyone ever treated some stock gears? Cryo or other wise... Or would the cost vs outcome not be worth it?

Mobius 11-18-2011 08:00 PM

The cheapest answer to "How do I make my 5spd stronger" is "Buy a used 6spd."

TNTUBA 11-18-2011 09:48 PM

^^^ All well and good....unless you are concerned about the gearing in the 6 speed SUCKING^^^


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