71 2800 CS throwout bearing

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audiokat

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A mechanic I've had "ok" luck with just diagnosed a throwout bearing on my 2800CS. It has a retrofitted getrag five-speed. It's a moaning noise on idle and accelerations at lower speeds that disappears when engaging clutch. I'm presuming they are correct but I have two questions form a novice

1. It is true the entire tranny need to be pulled to fix this? They said there's no reason not to just replace the clutch while it's pulled

2. Any advise on what I should be paying for something like this?
 
The throw out bearing only spins when the clutch pedal is engaged down, as it is pushed against the pressure plate to disengage and spins.
Seems that the noise is in the tranny.
Is there oil in the trans? Is the noise there at a stand still in neutral?
 
starcruiser said:
The throw out bearing only spins when the clutch pedal is engaged down, as it is pushed against the pressure plate to disengage and spins.
Seems that the noise is in the tranny.
Is there oil in the trans? Is the noise there at a stand still in neutral?
Click to expand...
No I don’t think I hear anything in neutral. Lord if they didn’t do consider fluid that would be something. The transmission fluid is certainly leaking. I haven’t this for long but I thought it was a sealed system. I went hunting for it the other day.
 
starcruiser said:
The throw out bearing only spins when the clutch pedal is engaged down, as it is pushed against the pressure plate to disengage and spins.
Seems that the noise is in the tranny.
Is there oil in the trans? Is the noise there at a stand still in neutral?
Click to expand...
He's saying the noise disappears when the clutch is engaged, not the clutch pedal engaged. Sounds like the throw out bearing.
 
Sounds like pilot bearing or an internal tranny bearing to me. If you press the clutch pedal and the sound goes away it’s because the force is off the pilot and tranny and on the throwout. When the clutch pedal is released, the force goes to the pilot and tranny bearings. Is this the correct scenario? Usually a bad throwout bearing makes noise when it is under load - when the clutch pedal is pressed.

Yes you need to remove tranny for either the throwout or pilot bearing. Therefore when doing this you should do pilot, throwout, and clutch at the same time. And an added bonus would be to consider replacing the rear main oil seal too.
 
audiokat said:
2. Any advise on what I should be paying for something like this?
Click to expand...
Depends on how many of the "while you're in there" items on Stevehose post above that you chose to do ("all" would be the right answer). The job won't be cheap, but most of the cost will be in removing and replacing the transmission. That's why it makes sense to perform all of the "while you're in there" items.

If you are not confident in this shop - and shouldn't be, since their diagnosis of a bad T/O bearing appears suspect - then getting a second opinion of the cause and a second quote for the repairs would be a good idea.
 
Stevehose said:
Sounds like pilot bearing or an internal tranny bearing to me. If you press the clutch pedal and the sound goes away it’s because the force is off the pilot and tranny and on the throwout. When the clutch pedal is released, the force goes to the pilot and tranny bearings. Is this the correct scenario? Usually a bad throwout bearing makes noise when it is under load - when the clutch pedal is pressed.

Yes you need to remove tranny for either the throwout or pilot bearing. Therefore when doing this you should do pilot, throwout, and clutch at the same time. And an added bonus would be to consider replacing the rear main oil seal too.
Click to expand...
Yea this all sounds correct to me. Pressing the clutch makes all sounds go away.
 
jmackro said:
Depends on how many of the "while you're in there" items on Stevehose post above that you chose to do ("all" would be the right answer). The job won't be cheap, but most of the cost will be in removing and replacing the transmission. That's why it makes sense to perform all of the "while you're in there" items.

If you are not confident in this shop - and shouldn't be, since their diagnosis of a bad T/O bearing appears suspect - then getting a second opinion of the cause and a second quote for the repairs would be a good idea.
Click to expand...
Good advise.
 
To summarize the above posts. The clutch throw-out bearing is NOT involved when the pedal is not pressed. It is sitting there doing nothing. At that time the clutch is "enaged" in that it it passing torque from the engine to the transmission input shaft.

When you press the clutch the throw-out bearing DIS-enagages the clutch, allowing the engine to rotate while the transmission gears are all stationary, so you can have the engine running and the car in clear and the engine doesn't stall.

So, if, as you say the noise occurs when the clutch pedal is not pressed (clutch engaged, pedal not engaged), and it disappears when the pedal is engaged (clutch non engaged), then the noise is coming from the transmission, not the clutch.

Does the noise appear when the transmission is in neutral and the clutch pedal is out? Or only under load (i.e., accelerating or driving at low speed)?

I concur with the forum that this sounds like an input shaft bearing, and yes, you need to pull the trans, and "while you are in there", replace the seal on the trans, and the engine, and replace the clutch and the throwout bearing. All of these are probably old, and it makes sense to do them when the trans and engine are separated from one another. Pulling the trans is not a major operation in these cars...

I do these jobs myself, so I have no idea what a mechanic would charge. I had a clutch done on a more modern car and that cost about $2K.
 
When the engine is running and the clutch is engaged, pedal down, the input shaft is spinning freely on the pilot bearing and the bearing in the trans, which will eventually would come to a stop with the clutch pedal down, so not the pilot bearing. The noise seems to be in the trans. when the clutch is released and the input shaft is turning and and spinning the layshaft. Check for fluid, but the trans, will need to be pulled and fixed.
 
Wow, the "clutch engaged" term has been misused about ten times in this thread.

Let's start over...
1) the noise occurs AT IDLE. This has to be the TO bearing or pilot bearing. They work in tandem, and if the car is not moving and the engine is running they are in use.

2) noise goes away as you start to move. See #1 above.
 
Let me clarify

1. Vehicle not moving = no noise.

2. Vehicle in gear while accelerating with the clutch pedal not depressed = Noise

3. Higher speeds little to not noise

4. Clutch pedal depressed no matter the speed, no noise.
 
audiokat said:
Let me clarify

1. Vehicle not moving = no noise.

2. Vehicle in gear while accelerating with the clutch pedal not depressed = Noise

3. Higher speeds little to not noise

4. Clutch pedal depressed no matter the speed, no noise.
Click to expand...
Thank you. This helps a lot. This would point towards the transmission internals then. Test one more thing... go through the gears and check if the noise goes away completely in fourth gear.
 
dang said:
Thank you. This helps a lot. This would point towards the transmission internals then. Test one more thing... go through the gears and check if the noise goes away completely in fourth gear.
Click to expand...
Does anyone have a diagram or a summary how the 265 works? Specifically, which gears move and how the torque is routed through the assembly in each gear?
 
ScottAndrews said:
Does anyone have a diagram or a summary how the 265 works? Specifically, which gears move and how the torque is routed through the assembly in each gear?
Click to expand...
I'm sure there's diagrams out there but it would be the basics. 1:1 gearing (4th gear in this case) goes straight through the gearbox. All other gears are routed through the lay shaft. Lay shaft bearings seem to make noise more often than the main shaft bearings on the boxes I've had.
 
As Dan noted it sounds like the layshaft bearing. When you depress the clutch or the car is in neutral and idling there are no forces on the layshaft. In the lower gears the forces are higher on the layshaft bearings for the same input torque, and in the direct gear (usually 4th but could be 5th if it's a dogleg box) the layshaft doesn't see any lateral loads so it shouldn't be noisy when in direct.
 
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