# new clutch



## Chris-Austria (Dec 23, 2010)

Hi!

Can I find out which clutch will fit my muncie transmission (4speed) without removing the old one first?
I'm not sure if the transmission is the original one, maybe it isn't a 4 speed muncie from 1966. In my catalog there are 10,5 and 11" disc sets for 10 or 26 spline transmissions. 4 choises.. only one will fit...

Chris


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## freethinker (Nov 14, 2009)

Chris-Austria said:


> Hi!
> 
> Can I find out which clutch will fit my muncie transmission (4speed) without removing the old one first?
> I'm not sure if the transmission is the original one, maybe it isn't a 4 speed muncie from 1966. In my catalog there are 10,5 and 11" disc sets for 10 or 26 spline transmissions. 4 choises.. only one will fit...
> ...


its probably a 10.50 with 10 splines.


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## Chris-Austria (Dec 23, 2010)

Is there a way to check it by a number on the transmission or something like this?
I don't want to remove and check it before I can order a new one... 
How long will it take to change the clutch on my car? Is it a very difficult job?


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## freethinker (Nov 14, 2009)

Chris-Austria said:


> Is there a way to check it by a number on the transmission or something like this?
> I don't want to remove and check it before I can order a new one...
> How long will it take to change the clutch on my car? Is it a very difficult job?


you can look at the year code on the trans. all 64-68 had 10 spline input and 27 spline outputs. some later model muncies had the 26 spline input but they also had fine spline output shafts(32)spline.
if you have a stock flywheel and bellhousing you have a 10.5 disc.

it is not hard to change. maybe 2 hours for someone who has done it before.


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## Indecision (Oct 24, 2010)

freethinker said:


> maybe 2 hours for someone who has done it before.


+1, even if you are just familiar with doing any RWD clutch swap, not specifically the goat.


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## geeteeohguy (Feb 2, 2008)

Be sure to mark your rear driveshaft yoke-to-u-joint before you pull the driveshaft. That way you won't get it out of phase. I've had really good results with LUK clutch kits....light pedal but plenty strong. You'll need to pull the flywheel and get it resurfaced to get the best results, too. Goes without saying, but remove the shifter before you pull the trans, and make SURE your throwout bearing is the same height as the one you removed. Also, install a new pilot bearing in the crankshaft. Driven right, clutches last a long time. I've had the same one in my '65 GTO since the mid '80's.


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## Chris-Austria (Dec 23, 2010)

Which clutch kit will be good for mainly street use and maybe 1-2 times a year the 1/8 or 1/4 mile drag?
Is RAM Automotive good? I'm thinking of medium or heavy duty... does heavy duty have any disadvantages compared with the medium?


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## freethinker (Nov 14, 2009)

Chris-Austria said:


> Which clutch kit will be good for mainly street use and maybe 1-2 times a year the 1/8 or 1/4 mile drag?
> Is RAM Automotive good? I'm thinking of medium or heavy duty... does heavy duty have any disadvantages compared with the medium?


ram looks good. if were me i would get this one.

HDX Performance Clutch sets 
GREAT DRIVEABILITY AND PERFORMANCE TO 450 HORSEPOWER


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## 66tempestGT (Nov 28, 2009)

geeteeohguy said:


> Be sure to mark your rear driveshaft yoke-to-u-joint before you pull the driveshaft. That way you won't get it out of phase.


could you explain this a little more please?


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## geeteeohguy (Feb 2, 2008)

I recommend LUK clutches for street driven cars. I have a McCleod in my '65.....its very Heavy Duty. The disadvantages of extreme duty clutches is usually high pedal effort and wear and tear on the linkage. The disadvantage of a weak clutch is slipage under load. 66Tempest, yes: the driveshaft should always be marked so it can be installed in the same position it was installed originally. Flipping it 180 degrees can sometimes result in driveline vibration. I've done a lot of u joints and driveshaft R&R, and this is SOP.


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## Chris-Austria (Dec 23, 2010)

I checked the numer on the transmission (3885010) and found out that I must have the 10 spline input. Maybe the transmission is from 1965.
Can I be sure that a 10,5" clutch will fit or is there a chance that I need the 11"?

If I remove the cover behind the starter, is it possible to see the old clutch and maybe a part number to make sure which one will fit?


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## freethinker (Nov 14, 2009)

Chris-Austria said:


> I checked the numer on the transmission (3885010) and found out that I must have the 10 spline input. Maybe the transmission is from 1965.
> Can I be sure that a 10,5" clutch will fit or is there a chance that I need the 11"?
> 
> If I remove the cover behind the starter, is it possible to see the old clutch and maybe a part number to make sure which one will fit?


if you have a stock flywheel its a 10.5


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## Chris-Austria (Dec 23, 2010)

I don't know if the flywheel is stock... will I have to remove it to be sure?
If it makes a difference.. the engine is a 428 from '69.


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## freethinker (Nov 14, 2009)

Chris-Austria said:


> I don't know if the flywheel is stock... will I have to remove it to be sure?
> If it makes a difference.. the engine is a 428 from '69.


to be absolutely sure i you have to remove it but 10 to 1 you have a 10.5.


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## likethat (Oct 5, 2007)

I like triple clutches.


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## Chris-Austria (Dec 23, 2010)

triple?


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## Chris-Austria (Dec 23, 2010)

If I search for a Hays flywheel for my 428 they say "the flywheel will accept 10,5" or 11" Borg and Beck or diaphragm-style pressure plates".

So the clutch itself is always the same size, there are only different pressure plate sizes? So if the flywheel will accept both.. it doesn't matter which clutch kit I buy??


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## geeteeohguy (Feb 2, 2008)

The flywheel is universal. It will accept both 10.4 and 11" clutches. And the disc and pressure plate are both bigger on an 11" than a 10.4". If you get the universal flywheel, you can run either one without issue. They will both work just fine.


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## freethinker (Nov 14, 2009)

Chris-Austria said:


> If I search for a Hays flywheel for my 428 they say "the flywheel will accept 10,5" or 11" Borg and Beck or diaphragm-style pressure plates".
> 
> So the clutch itself is always the same size, there are only different pressure plate sizes? So if the flywheel will accept both.. it doesn't matter which clutch kit I buy??


yes if you are already have or are buying a new flywheel. but if you have a factory 10.5 setup a 11inch disk and plate will not work.

a tripple disk clutch is a racing setup. overkill for the street. just depends what you want to do.
triple disc | eBay


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## geeteeohguy (Feb 2, 2008)

The flywheel is universal. It will accept both 10.4 and 11" clutches. And the disc and pressure plate are both bigger on an 11" than a 10.4". If you get the universal flywheel, you can run either one without issue. They will both work just fine.


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## Chris-Austria (Dec 23, 2010)

I've checked my old clutch and I can see that it is orange. On summitracing the only orange clutch is from Centerforce and always 11".
On the flywheel I could find the number "8621677" maybe there are 1 or two numbers before but I couldnt see it good enough.There was also the number 851826.

Is it possible to check if it's an universal flywheel or stock?

Here is a picture:
http://members.chello.at/cg-tuning/clutch.JPG


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## geeteeohguy (Feb 2, 2008)

What you need to do is pull the trans, remove the clutch, match it up, and remove and resurface the flywheel. You'll be good to go. No mater what's in there, you'll be able to match it up. The car will not be out of action for long, in any case.


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## Chris-Austria (Dec 23, 2010)

That sounds good, thank you 

What do you think of aluminium flywheels? They have half the weight (15lb instead of 30lb). Maybe I'll use a new lighter one if it doesn't have any disadvantages and if I do so I don't have to worry if the clutch will fit.

The shop where I buy my parts have following clutch kits for sale, which one do you think is best for street use and once or twice a drag race every year? I'm not driving around so much, if the pedal is a litte bit harder I'll survive it  The engine produces probably about 350-400hp, I don't think that I will upgrade it much... If the clutch can handle up to something between 400-450hp it is enough.

Here are the available kits:

1. Centerforce dual friction (organic/carbon)
2. Centerfoce DFX (ceramic)
3. Ram Powergrip (iron organic)
4. Ram Powergrip HD (iron organic)
5. Mc Leod Super Street Pro (organic/ceramic)
6. Hays Steet/Strip (organic)


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## geeteeohguy (Feb 2, 2008)

I haven't put a clutch in mine since about 1984, and it's still in there. It's a McCleod unit, 3400lb rating, if I remember. Works great, but fairly high pedal effort. I've installed LUK clutches in a few GTO's, and like them a lot: very light pedal effort and plenty of holding power. It will be my next clutch, if I ever wear out the old McLeod. Stick with a steel flywheel: more inertia means easier starting and increased torque. Aluminum flywheels belong on high-revving small block engines that have little torque but lots of horsepower.


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## Chris-Austria (Dec 23, 2010)

Good to know, so I'll try it with a clutch kit and the resurface the old flywheel.
What can I do if the clutch kit won't fit? How can I match it up?
I'll search the internet for LUK clutches.. but if I can't find one that ships to Austria, does anybody know some of the clutches I listed?


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## Chris-Austria (Dec 23, 2010)

Now that I rebuild my engine can you tell me what clutch material will be best?
A sintered metal will be not really good for street use I guess?
I want light-medium pedal effort and enough holding power.. most times it will be used on the street!
Organic, Kevlar, Ceramic or some mixture? (if it can handle about 500 torque and 400 hp it will probably be enough)


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## ALKYGTO (Mar 29, 2010)

Chris - I'd call or email Mcleod and ask them for a recommendation. That's what I did after smoking another brand "high performance" clutch in my heavy, overpowered GTO and they were more than helpful. I bought what is called a 12" "cheater" clutch they offer. Single disc, good supposedly to 1000 hp. 

It's worked beautifully so far holding the power except this year I have noticed that it seems as if the pressure plate is "losing tension" in that I have to put the pedal all the way to the floor to shift now and adjusting it made little to no difference. I've had it in the car for about 5 years, limited miles but hard use .

Mcloed also offers a "street twin" setup and I will probably step up to that next season.


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## Chris-Austria (Dec 23, 2010)

Thank you!
I finally know what size I need. I need a 10 3/8" disc and have a 10 spline. 
For example these 2 would work, I only need to decide which one is the better choise:

1. Centerforce Dual Friction:
http://www.summitracing.com/parts/ctf-df271675/overview/year/1966/make/pontiac/model/gto

2. Mc Leod Super Street Pro:
http://www.summitracing.com/parts/mcl-75217/overview/year/1966/make/pontiac/model/gto

Both are good for street use... My engine will make about 450hp I guess, so there is no need for a clutch that holds up to 1000hp.

Which one might be better?


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## Chris-Austria (Dec 23, 2010)

I have a question.. will the 10 3/8, 10.4 and 10.5" clutch sets all fit on a flywheel that cannot be equipped with the 11" disc?

My flywheel has been tested with an 11" disc which would normally fit the 428.. but it didn't. After that the mechanic measured it and told me that it has 10.375".. but for example Centerforce does only build 10.4" and the (non-fitting) 11". Ram only builds 10.5" for all Pontiacs that don't need 11".

Whats the deal with that?


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## ALKYGTO (Mar 29, 2010)

Just for reference the "10.4" is 10.400" (inches) and if your mechanic said 10.375" (inches) then thats what you want. Difference is only .025 of an inch.

Be sure to have your flywheel resurfaced also so the clutch disc has a fresh surface to bed to.


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## Chris-Austria (Dec 23, 2010)

Okay I hoped you say so  I like to measure in "mm" and the difference is only 0.5mm.. 
He has already resurfaced the flywheel and tried the 11" disc set => too big for it.
So I'll give the new one to him on Monday and I guess it will fit (google told me that 10.4 is the same as 10.5).

My plan:
- resurface the flywheel
- use a new throwout bearing from centerforce
- have a pro to install it
- drive 400-500 miles for break in without full throttle


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## Chris-Austria (Dec 23, 2010)

Another question...
The old clutch slipped (probably because of the grease that was on the disc as I know now) but the pedal was also "strange". When I drove fast I could her the pedal "vibrate" and to stop the noise I could either lay my foot on it just to touch it carefully (without disengaging the clutch) or I could make the opposite and pull it from behind with the left leg (about 1inch maybe until it didn't go any further).

What could cause this? I know the trowout bearing was bad, the clutch was greasy and the flywheel needed to be resurfaced. Could this have caused all my problems or is there a way to adjust it with the new clutch for not having the problem with the pedal again?

Also after driving around for a while and the clutch was hot I guess I sometimes had problems shifting from 1st into 2nd gear at higher rpm's. Could this have been caused by the grease on the disc? (shifting slowly was never a problem, but if you want to accelerate it isn't fun to shift like your grandpa)

I don't really know much about clutches and how they work, so I have no plan how the system looks like and what can cause this problem.. is there a mechanical linkage? Because I don't think there is a hydraulic for the clutch like my BMW had...


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## leeklm (Mar 11, 2012)

Most likely the vibration you are hearing is the mechanical clutch linkage rattling. You could have too much slop in the connecting points such as a worn out z-bar. Mine does the same thing. My headers prevented me from adjusting the fork push rod in order to take the slop out of the linkage. I am replacing everything this winter, including the headers, so should be able to get things adjusted appropriately. I assume there is a "proper" way to adjust the clutch travel, but I am not 100% sure of the correct method. Should be able to find it in a factory manual or google search.


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