Anyone know how to change throw out bearing??

[Johndeere120]

Yeah the oringal tag actually got lost it came off one day and I lost it somewhere but I could've sworn 1979 only had the big cam 1. But I have no idea maybe you're right though could be the big cam 2

 

[mitch504]

Big cam 2 came out in '79, I think.

 

[Johndeere120]

I'm new on this can I post a video of the sound so you guys can hear? The throw out bearing is one thing, but i dont know if it's also causing rattle it's so annoying

 

[Delmer]

Post it on you tube or somewhere and post the link here, i think that's the easiest way to do it. Any chance you could take some pics through the inspection cover?

 

[funwithfuel]

Might just be the center plate rattling around.

 

[Johndeere120]

Yeah maybe tomorrow or Monday I'll be able to for sure

 

[Truck Shop]

The last of the small cams were produced in 1975, the Big Cam came on board in 1976. Although Cummins continued to build and install small cam engines for the Gov/military into the 1980's.
{A video would be great}. One other source of noise produced in the Cummins 855's with PT pump is the {vibration damper} especially at idle where there is a narrow rpm band. The torsional vibration
created by the bottoming of the compression stroke will cause excessive transmission growl at idle. Raise the rpm from 600 to 700 and it normally disappear. Now that being said it doesn't mean
the throw-bearing in your truck isn't bad. But the total life expectancy of the vibration damper is 380,000 miles and I would expect if you sanded the paint off the front of the vibration damper
you would find a name of {Hydraulics Houdaille} a company that hasn't been in business for some time. I would bet it still has the original damper, Houdaille built all the dampers for Cummins,
Cat and Detroit if those companies used viscous dampers. In most cases by installing a new damper the transmission noise disappears, but a bad vibration damper will cause broken crank shafts,
cam shafts, accessory drives and will effect valve and injector timing. There is no real way to diagnose or inspect a damper except for measuring the thickness of the damper and even that is not
reliable. But the silicone in the damper will harden after so many heat cycles and age, So most likely a very high percentage of engines are running with a trash vibration damper and a bunch of
transmissions are diagnosed as worn gear train when the problem is torsional vibration.

It is recommended that the vibration damper be replaced on any in-frame or major engine rebuild-but 90% of mechanics or repair shops including dealers never do it.

 

[Johndeere120]

The last of the small cams were produced in 1975, the Big Cam came on board in 1976. Although Cummins continued to build and install small cam engines for the Gov/military into the 1980's.
{A video would be great}. One other source of noise produced in the Cummins 855's with PT pump is the {vibration damper} especially at idle where there is a narrow rpm band. The torsional vibration
created by the bottoming of the compression stroke will cause excessive transmission growl at idle. Raise the rpm from 600 to 700 and it normally disappear. Now that being said it doesn't mean
the throw-bearing in your truck isn't bad. But the total life expectancy of the vibration damper is 380,000 miles and I would expect if you sanded the paint off the front of the vibration damper
you would find a name of {Hydraulics Houdaille} a company that hasn't been in business for some time. I would bet it still has the original damper, Houdaille built all the dampers for Cummins,
Cat and Detroit if those companies used viscous dampers. In most cases by installing a new damper the transmission noise disappears, but a bad vibration damper will cause broken crank shafts,
cam shafts, accessory drives and will effect valve and injector timing. There is no real way to diagnose or inspect a damper except for measuring the thickness of the damper and even that is not
reliable. But the silicone in the damper will harden after so many heat cycles and age, So most likely a very high percentage of engines are running with a trash vibration damper and a bunch of
transmissions are diagnosed as worn gear train when the problem is torsional vibration.

It is recommended that the vibration damper be replaced on any in-frame or major engine rebuild-but 90% of mechanics or repair shops including dealers never do it.

That is very interesting never knew that. The guy before had an inframe done around 700k it's got 800k so I'm 99% sure its original dampener. So since the company you mentioned is no longer in business, is it possible to even get another one now? And how hard is it to change just unbolt it from the front and it comes right off?

 

[Truck Shop]

Yes you can still get one, and some are high dollar. Highway and Heavy Parts. com sells aftermarket with two year warranty IIRC. Around $300.00. If you decide to change it you will
need to measure the total outside diameter, such as the higher horse power like 400 hp and up use a 13.5" damper. Normally the lower hp engines use a 12".

Remove the alternator belts and remove the damper bolts, the pulleys behind it are removable. To install {torque the damper bolts to 115 LBFT.} It weighs about 40 lbs.

 

[Johndeere120]

Yes you can still get one, and some are high dollar. Highway and Heavy Parts. com sells aftermarket with two year warranty IIRC. Around $300.00. If you decide to change it you will
need to measure the total outside diameter, such as the higher horse power like 400 hp and up use a 13.5" damper. Normally the lower hp engines use a 12".

Remove the alternator belts and remove the damper bolts, the pulleys behind it are removable. To install {torque the damper bolts to 115 LBFT.} It weighs about 40 lbs.

Okay sounds easy enough. Maybe I will try it I'm glad you mentioned it because I would literally never have even thought about that in a million years. When I give it ANY fuel just to raise rpms even 30-50 sounds goes away and run smooths so I bet that actually is it I just couldn't figure it out. Also I know on mine there are 2 partially drilled holes I'm assuming that's some type of timing mark? If so I'll be careful to mark where it came off

 

[Truck Shop]

IIRC the part number for that damper is 211915, it should be on the face somewhere below the manufacture name. Also if it's drilled it could be the type that is rubber mounted and those can slip. But a picture would
be nice if you can get one.

 

[Johndeere120]

Okay might head to the shop in the morning if I have time. If not I'll get pictures and videos of everything Monday morning

 

[Johndeere120]

IIRC the part number for that damper is 211915, it should be on the face somewhere below the manufacture name. Also if it's drilled it could be the type that is rubber mounted and those can slip. But a picture would
be nice if you can get one.

Here's some videos I took this morning I forgot the take a picture of the damper but I got the rest hopefully you can hear the rattle I'm talking about it's hard to hear it in the video because the engine is so loud

 

[Johndeere120]

 

[Johndeere120]

 

[Johndeere120]

 

[Johndeere120]

 

[Truck Shop]

Nice videos-Yes there some slack in the throw-out bearing but it will move some. And both throw-out bearing and noise created by torsional vibration will go away by depressing the clutch.
That's why it's hard to diagnose. And I have witnessed that same noise even with a new clutch installed and in one of the videos it comes and goes. Which leads me in the direction of the
damper IMO-for what that's worth which usually isn't much. And it looks to be a 14" clutch.

 

[Johndeere120]

Nice videos-Yes there some slack in the throw-out bearing but it will move some. And both throw-out bearing and noise created by torsional vibration will go away by depressing the clutch.
That's why it's hard to diagnose. And I have witnessed that same noise even with a new clutch installed and in one of the videos it comes and goes. Which leads me in the direction of the
damper IMO-for what that's worth which usually isn't much. And it looks to be a 14" clutch.

So a new throw out bearing even has a little slack? I'm going to order a damper and see if that helps first before pulling the trans. Anither strange thing I should mention is when I start it cold in the morning it usually doesnt rattle hardly at all. But once I run it and warmed up it does it more often but still comes and goes so hopefully its just the damper because I bought it off a guy i still know and he said it had the same rattle for 20 years since he bought it

 

[Truck Shop]

Cold the engine is usually slightly below the rpm range idling at 550 as soon as it warms it hits 600 then the noise starts, when it climbs to 650 it goes away.