The "I blew my gearbox with a HD clutch" thread

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The "I blew my gearbox with a HD clutch" thread

Postby Random Dude » Wed Nov 07, 2007 10:01 am

This is a public service announcement!!! :smart:


HELP..I think i blew my GEARBOX..!!

xcwizit wrote:As soon as the lights turned green, I stayed in 1st gear waiting for the REVS to pick up slowly, as soon as it hit 5k-6k rpm, I planted the acc. pedal, quikly slapped it in 2nd gear. then suddenly i heard a LOUD BANG from the front of the car. I've got an Exedy Heavy Duty Clutch which was installed Dec 06 incase its any help.

Gearbox and tranny

gilese98 wrote:Got myself a 98 WRX wagon and was just comming home from work, Stoped took of again went from 1st to 2nd and crunch then nothing...

i've recently put a Exedy Heavy duty clutch in also if that makes your answers any different!!

Blew My Gearbox Again !!!

PSIXTC wrote:When i bought it 1st week i blew 2nd gear...then i got a full rebuild on the gearbox and put a cusion button clutch in was fine for about a week. Then the same thing happened but this time it was 3rd gear... And yes i launched once of the lights, Drop the clutch at about 4000rpm. But nothing else i dont understand why...

Anyone tried exceedy racing clutch?

InFlames wrote:Hi, as above, has anyone put an exedy racing clutch into their wrx?
I just did and my car is experiencing the worst shudders ever, especially so when moving off, I'm told this is normal, anyone have experience with this?

my 2nd gear died today....

BaZeRk0 wrote:Know the fealing you going through right now as i too hadn't had my wrx'y long when i blew 2nd gear. I had a heavy duty clutch put in, had it for 2 days then bang blew second gear :x ....

drewcreighton wrote:I know this is a common issue.. high end engine mod... (idiot *me* :chair: ) puts in a HD clutch.. tick...tick..tick... kaboom goes the gearbox... :wall:

:smart: :smart:

cpitts wrote:How many times does it need to be said "DON'T install a HEAVY DUTY clutch!" It'll only end in shredded gearboxes. :(

thanGy wrote:Factory clutch is best

MrEs wrote:throw ur heavy duty clutch in the bin before you need an entire new gear box...

superfly wrote:As mentioned the heavy duty clutch is bad for the stock gearboxes. It puts all the strain on the box rather than on the clutch itself.

superfly wrote:Even then I'd stick with the stock clutch. Unless you're doing lots of launching (drag racing etc) and each split second counts. If you upgrade the stock clutch to a heavy duty item with a strong gearbox, next to go will be the driveshafts.

Howdy wrote:You replaced the OEM clutch with a button clutch which made the gear box the weak link in the drive train.

Instead of the OEM clutch being able to slip the gear box gave away.

KevO-954 wrote:You may get away with launches most times in a two wheel drive as the tyres will break traction therefore not loading the rest of the drive train severely but with AWD you are not going to break traction that easily so the drive train is under extreme stress and something has to give. Kev. :wink:

PAT555 wrote:As I suspected its the cushion button clutch.
BIG NO NO on a standard gearbox.

You should of done your research.

T WRP10 wrote:if you got a wrx and a stock box with a racing clutch.. its going to do damage

BlueDNA wrote:options that you have now are:
- Rebuild gear 2 and put standard clutch back on
- Buy sti gear box 5/6spd (about 4k~5k) and keep heavy duty clutch
- Rebuild with PPG gears

Random Dude wrote:All i can advise is, and this has been seen time and time before:

If you're running your standard gearbox, its not a good idea to use any sort of heavy duty clutch system.

The clutch is what protects the gearbox from being ripped apart from the torque of the engine. Even with standard power. The clutch is meant to slip when power is too great, and the resistance from the 4WD is too great (and you have your gearbox in between)

What you'll find is, if you get a heavy duty clutch, it won't slip, and instead send all that torque to your gearbox and bang, there goes 1st or 2nd (or 3rd).

kooky wrote:HD clutch + gearbox abuse will lead to box full of broken gears, nothing surer in a WRX.

Quote submissions welcome!

And now all the keywords so people can actually search this:

clutch cusco exceedy heavy duty race gearbox launch 1st 2nd 3rd gear gone blow blown tooth bang scrape heavy duty clutch shifter drag idiot
Last edited by Random Dude on Wed Nov 07, 2007 10:29 am, edited 3 times in total.

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Postby kooky » Wed Nov 07, 2007 10:14 am

kooky wrote:HD clutch + gearbox abuse will lead to box full of broken gears, nothing surer in a WRX.

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Postby Pokiou » Wed Nov 07, 2007 10:24 am

yea i had a stockish clutch in my 180sx.. very easily held 220+ rwkw :)... plenty of launchs and so forth... i think that the only reason why a heavy duty button clutch or that sort would be useful is on the track... once you launch thats it.. you dont need to stop... in which case 90% of race cars change there clutchs after every event/race so forth...

so for those that blow there gearboxs with super duper mega hyper grippy clutchs...

serves you right ;)

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Postby 05-RSX » Wed Nov 07, 2007 10:52 am

For those electrically minded, the clutch is the fuse in the drivetrain. If you run a HD clutch with the stock gearbox, it's like running a 50A fuse with wire than can only handle 20A - useless.

da_dvs_1 wrote:Now you just need to get everyone to do a search before posting :?

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Postby MrEs » Thu Nov 08, 2007 11:28 pm

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Postby cured5.7 » Thu Feb 07, 2008 2:45 pm

For those that want to know:

Exedy (Daikin) makes a heavy duty version of the stock clutch assy,
without the need for any sort of button clutch version, they have better material on the plate and more clamp pressure on the Pressure Plate.

We have fitted plenty of these to WRX's and none have comeback with gearbox problems.
They arent as harsh on the old gearox and alow the enough slip to transfer power more smoother through the drive train.


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Re: The "I blew my gearbox with a H/D clutch" thread

Postby PAT555 » Sat Feb 23, 2008 9:51 pm

Correct your actually speaking of the STI clutch. Thats what I put into my car.
Well thats what I was led to believe its the GC8 STI clutch.
The older I get the slower I drive.

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Re: The "I blew my gearbox with a H/D clutch" thread

Postby bazzasti » Wed Mar 26, 2008 7:27 pm

I've just finished up a fair bit of testing and found that the gearchange and application of power has more to do with breaking the box than the power.

I drove around for about two weeks with a stock MY01 (8 bolt) box using full power (280 kw) through all the gears and it was fine with a 2700 lb brass button clutch. Basically I would change gear, alloy the slack to be removed from the driveline and then give it to her - usually about 0.5-1.0 second after releasing the clutch.

However the first flat change and clutch drop from first into second stripped all teeth from 2nd gear on both input and output shafts.


Something I should add is a 2200 lb or less brass button padded centre clutch is 100 times better to drive on the street than stock or heavy duty clutches. For some reason stock and heavy duty feel very heavy on the leg.... brass button with padded cores are very light. 2700 lbs is a touch heavier but still not bad. The car is driven every day and I'd prefer the lighter clutch.... wouldn't you?

I also broke PPG 2nd gear tooth - but that took about 2000 repeated efforts.... metal fatigue dammit!


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Re: The "I blew my gearbox with a HD clutch" thread

Postby Dr. TEMTNU » Sun Feb 22, 2009 3:05 pm

i can relate to that i got my rex about 7 months ago and there was a heavy duty clutch in it and the guy had snapped the rod that holds the gears together the gear box place in nunawading had no idia on how it had snapped but the idiot i got the car off put truck oil in the gear box so the ticking noise would go away (doddgy) and when i got my gear box replaced bcos it was $3500 damage so i got another one he guy at the gear box place goes to me dont put heavy duty clutch in a wrx put a standerd clutch i did and have never had a prob sence
your pathetic

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Re: The "I blew my gearbox with a HD clutch" thread

Postby droid » Wed Jun 10, 2009 11:40 pm

This was second gear when I blew up my box a few months ago.......

Image Image

HD clutch + stock g/box + poor driving technique = BOOM
M99 GF8 WRX Wagon - EJ25 sti,VF35,Unichip,3" tbe, APS cai + some other bits and pieces........

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