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Author Topic: Clutch brake -- do I ask for anything special?  (Read 4142 times)
Brian Diehl
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« on: May 02, 2007, 07:15:07 PM »

I pulled the Eaton Autoshift off the Cummins ISM tonight.  The clutch looks to be in great condition -- maybe very recently replaced.  I was very pleased with how easily it came apart ... much easier than I had anticipated and worked myself up for!   Grin

However, it looks like the clutch brake was not replaced when the clutch was.  Before I call and try to get a replacement I thought I would ask for an education on things I should know or ask for.  What say ye ... anything I need to know before I call ... or do I just call and ask for a replacement?  If it matters, the clutch is an IATCO M-496 -- dual plate clutch.

Thank you in advance for any advice.
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belfert
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« Reply #1 on: May 02, 2007, 07:50:04 PM »

What exactly is a clutch brake?

I've never owned or had any desire to own any vehicle with a manual transmission so I have no experience with them.  I can drive a pickup with one although I hadn't for about six or seven years until last summer.  (Most cars have a very different clutch feel from a pickup and I can't drive a car with a manual tranny.)

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Sojourner
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« Reply #2 on: May 02, 2007, 07:52:25 PM »

I wasn't aware it has a "clutch brake" till you mention it. Now I know why they can shift sooner than old type.
Thanks
Here a link for others who might be of interest:
http://www.heavydutytrucking.com/2005/02/064a0502.asp

If are not sure of its condition..take the "clutch brake" part to a heavy truck repair shop to get their feed back.

I believe it to slow down input shaft until match gear ratio to engage.

FWIW

Sojourn for Christ, Jerry
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buswarrior
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« Reply #3 on: May 02, 2007, 07:53:40 PM »

Clutch brake will stop the internals of the manual tranny from spinning, so they will mesh together.

Clutch brake is engaged by pushing the clutch all the way to the floor.

VERY BAD to push the clutch all the way to the floor while the vehicle is moving, causes a rapid wear and failure of clutch brake to function as intended.

Rare in a bus transmission, common in the multi gear tractor trailer transmissions.

Edited: clutch brake is to engage the gears while sitting still, old GM drivers know what I mean about spinning gear sets waiting at the lights.

Clutch brake is NOT for use while underway. Never mind what some trucker has told you...

happy coaching!
buswarrior
« Last Edit: May 02, 2007, 07:56:28 PM by buswarrior » Logged

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« Reply #4 on: May 02, 2007, 08:21:20 PM »

Brian, Buswarrior is right on. It only is used to stop the gears from rolling when you go from neutral into low or reverse. If you use it any other time it will destroy it. The auto shift is not using it. There is an aftermarket unit available that comes in two pieces that interlock. You just seat a roll pin to keep it in place and can replace it without removing the transmission. I think this piece is superior to the factory unit. These replacement clutch brakes are around $20. I haven't bought one lately and don't have a part number handy but I'll look around the shop. The other thing you need to know to get the right one is the input shaft size.
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lloyd
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« Reply #5 on: May 02, 2007, 09:25:10 PM »

If you go to any truck dealership - KW, Peterbilt, Freightliner, etc and ask for a clutch brake for an auto shift they will give one no problem. If you put in a two piece you can change it without removing the trans. Another item you might want to change while the clutch is removed is the pilot bearing in the flywheel. Again it is not expensive but this would the time to change it.
Lloyd
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Brian Diehl
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« Reply #6 on: May 03, 2007, 05:49:05 AM »

Another item you might want to change while the clutch is removed is the pilot bearing in the flywheel. Again it is not expensive but this would the time to change it.
Lloyd

What tool would I use to get the old one out without removing the clutch?  It is a LONG way from into the clutch and I don't have a puller narrow enough or long enough to get down to the bearing.
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larryh
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« Reply #7 on: May 03, 2007, 06:57:52 AM »

Brian

Make sure you have the numbers off of the tranny serial number . model etc.

To pull the pilot bearing clutch must be pulled also be good time to check face of flywheel might need to be refaced if any clutch chatter especially in reverse HTH

LarryH
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lloyd
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« Reply #8 on: May 03, 2007, 07:43:23 AM »

With the clutch removed you can use a slide hammer to pull the pilot bearing, or remove the flywheel and drive it out from the other side.
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TomC
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« Reply #9 on: May 03, 2007, 08:42:53 AM »

Brian- at least at Freightliner, all parts are pulled up from the last six digits of the trucks serial number.  Do you have the make, model and serial from the truck that the transmission came from?

Clutch brakes have been used for years-at least the 30 years I've been in trucking.  This is where alot of owners get in trouble when they try to adjust the brake with the clutch linkage.  There is a definite sequence to adjusting a clutch with a clutch brake.  And if you have an Autoshift, you're supposed to have the Eaton "Solo" clutch that automatically adjusts itself.  If you don't have that clutch (which sounds like you don't) you should seriously consider installing the clutch that is required for proper operation of the Autoshift transmission.  Because of the sensors in the transmission, the clutch can NEVER slip, or the sensors will wrongly advise the engine to accelerate more, which quickly destroys the clutch.  This is why the Solo clutch is used since the transmission relies on accurate synchronization between the engine and transmission (all shifting is done on rpm timing).  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Brian Diehl
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« Reply #10 on: May 04, 2007, 07:35:52 AM »

Talked to Freightliner and they had no problem looking up the right brake.  The brake is going to cost a big $11!   Grin

I find out the clutch is made by Illinois Auto Truck Company.  Their website is here:  www.iatcoinc.com/eng/home.asp

I'm still tracking down all the information for adjusting the clutch, but so far looks like an easy process from what their tech support described.  At this moment I'm not pulling the clutch off unless I find something else that leads me to conclude pulling the clutch is necessary. 

However, I will be fashioning a cover for the bottom access into the bell housing.  I found about 5 - 6 lbs of dirt crusted up inside the bell housing.  The nice thing about cleaning out the dirt was all the dust it created on my garage floor absorbed a bunch of the oil I'd spilled earlier and "cleaned" up the look a bunch.   Cheesy
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TomC
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« Reply #11 on: May 04, 2007, 09:10:47 AM »

I called IATCO and gave them the M-496 number.  That is just the number of the clutch cover-of which there are about 35 different clutches with that number in it. 
While Eaton insists on their SOLO clutch for OEM installing when new, evidently some put in manual clutches.  My suggestion is you learn how to adjust your clutch properly to maintain the clutch brake operation.  Basically, it involves first adjusting the clutch (internally-no at the linkage) and once adjusted, then going to adjust the clutch brake.  If allowed to slip, the engine can overpower the clutch and quickly burn it up-so keeping on top of adjustment with the Autoshift is very important.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Brian Diehl
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« Reply #12 on: May 04, 2007, 09:20:32 AM »

Thanks Tom.

I had called them and come to the same information.  I'm going to learn how to adjust it before I put the tranny back on so I can do a final adjustment once put back together.
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