Why do gears break on the stock transmissions?
My 6-speed use to grind almost every 1-2 and 2-3. Switched to MT-90 and they were gone within 3k miles. Just jumped to Amsoil/GM Synchromesh and they've stayed gone.
BTW - 3 trannies in 16k miles isn't ridiculous. I broke my 5 after 6k. thesnowboarder broke his at under 200whp after 1500 miles.
BTW - 3 trannies in 16k miles isn't ridiculous. I broke my 5 after 6k. thesnowboarder broke his at under 200whp after 1500 miles.
Last edited by Savington; Sep 15, 2009 at 12:06 AM.
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I have broken 6 of the 5 speeds. Driving style has very little to do with it. 300+ ft-lbs of torque and R-compound tires kills them in a short amount of time. I’ve broken 2nd twice, 3rd, twice and the gear that drives the secondary shaft and all gears but 4th twice. Gears stripped clean off.
I think I will try and find a cheap 6 speed until I can save the money for the Quafe. I still hate the gearing on the 6 speed. The problem I am having is I keep on getting 5 speeds for $75 or less and I haven’t found a 6 speed for less than $700.
Bob
I think I will try and find a cheap 6 speed until I can save the money for the Quafe. I still hate the gearing on the 6 speed. The problem I am having is I keep on getting 5 speeds for $75 or less and I haven’t found a 6 speed for less than $700.
Bob
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I've been to the drag strip once with this car, so hard launches have very little to do with it. I drive my car hard, but I'm certainly not hashy with the gears. I drove this car for a year N/A and never had any problems. I've also been driving manual cars for over 7 years and never broke a box before.
It seems that the boxes plain can't handle the power. That, or maybe its Flatshift...
It seems that the boxes plain can't handle the power. That, or maybe its Flatshift...
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Joined: Jun 2006
Posts: 29,085
Total Cats: 375
From: Republic of Dallas
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Joined: Jun 2006
Posts: 29,085
Total Cats: 375
From: Republic of Dallas
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Elite Member
Joined: Jul 2005
Posts: 2,502
Total Cats: 146
From: Anacortes, WA
I was making it through about 4 track days previously before upgrading the ECU and a few other things which upped the output a small amount.
Bob
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ah my mistake i got cross posted bundy you are well past the know dangerzone for a stock five speed and need to consider doing something about it seriusly. No one has held much hope of more than 250 lb/ft through a stock tranny for any amount of time or abuse. For a long time. Either the FM gearset or the 6 speed would pay dividends for you.
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Edit:
Here it is, quoting savington from an m.net thread:
6-speed with 3.636 final
34.6 in 1st
57.3 in 2nd
79 in 3rd
103.4 in 4th
129.9 in 5th
154.1 in 6th (2952rpm @ 65mph, 3406rpm @ 75mph)
The idea of going from a 5sp with 4.3 to that is giving me a semi. I definitely know what i'm saving for this winter.
Last edited by wayne_curr; Sep 15, 2009 at 01:45 PM.
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6 speed box....... crossing the quartermile in 5th gear FTL.
Having said that, if it proves to be a durable solution then I'm all for it. Especially if it gives me a bit lower RPM when cruising on the motorway.
Having said that, if it proves to be a durable solution then I'm all for it. Especially if it gives me a bit lower RPM when cruising on the motorway.
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Here's the FM gear ratio calculator. Factors in tire size, 5 or 6 spd tranny, desired max rpms and has ratio's for the quaife gear sets too. Damn helpful tool.
Flyin' Miata : Technical info : Gearing calculator
I'd do a queef 5 speed gearset if it didn't cost as much as my entire car. I'm looking for a cheap 6 spd to go with the 3.63s I just got.
Flyin' Miata : Technical info : Gearing calculator
I'd do a queef 5 speed gearset if it didn't cost as much as my entire car. I'm looking for a cheap 6 spd to go with the 3.63s I just got.
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Junior Member
Joined: Sep 2008
Posts: 263
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If the grinds went away after 3K, why did you change again?
So what oils are everyone else using? I had planned to change that out soon after I got it running, but I don't know what oil is best for tranny longevity.
I am a firm believer in updating tranny oils, with VWs you can't help but crunch every aggressive shift into 2nd, but with MT90, I can downshift into 1st while rolling (no synchro on that gear, that might be on all manuals).
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Elite Member
Joined: Jul 2005
Posts: 2,502
Total Cats: 146
From: Anacortes, WA
Here's the FM gear ratio calculator. Factors in tire size, 5 or 6 spd tranny, desired max rpms and has ratio's for the quaife gear sets too. Damn helpful tool.
Flyin' Miata : Technical info : Gearing calculator
I'd do a queef 5 speed gearset if it didn't cost as much as my entire car. I'm looking for a cheap 6 spd to go with the 3.63s I just got.
Flyin' Miata : Technical info : Gearing calculator
I'd do a queef 5 speed gearset if it didn't cost as much as my entire car. I'm looking for a cheap 6 spd to go with the 3.63s I just got.
Bob
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I have a spare 6-speed I may be selling off here in a couple of weeks if anyone is interested. I'm checking with the local crowd first to see if any of my Miata buddies want it. If not, I'll post it in the classifieds.
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Newb
Joined: May 2009
Posts: 12
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From: Currently in Bielsko-Biala Poland
Weight of the car also has a significant impact on the stress the transmission receives. That said, I'm not sure that even removing a couple hundred pounds off a miata is going to improve the life of the 5 speed that much...
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