Gearbox noise

I am hoping it's not the input shaft bearing, what kind of Redline gear oil did you use?

 

You might want to try Swepco 201

 

Did he change the Pilot Bearing? The clutch has both a throw out bearing and a Pilot Bearing. If you depress the clutch pedal and the sound goes away, its one of these two.

It is also possible to adjust the throw out bearing to much so it rides the clutch when not engaged. This will cause a noise and will wear out the bearing much faster.
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I had a similar noise, turned out to be the bearing that's pressed into the bell housing, it's a double row ball bearing and supports the shaft and top transfer gear. not a cheap bearing, all new bearings for the bell housing that support the drop gears is around $1200.

sounds like a grinding rattle at idle and goes away with the clutch depressed.

#20 in pic above

 

It would help to have a bit more diagnostic information.

Does it make the noise when the car isn't moving?

If the noise is only when the car is moving then does it make the noise in neutral when moving?

 

Glassman,

Did you ever figure out what the noise was from? I have exactly the same problem - whirring/rattly noise at idle, that goes away when the clutch is depressed. I took the transfer case cover off and found mismatched transfer gears and evidence of loosening of the bottom gear in the past- the inside of the transfer case cover was badly scored. So far I've replaced the gears with a matched set, and the center gear bearings and... the noise is as bad as it ever was. That was a rather expensive troubleshooting maneuver. I'm running redline 75-90 NS in the transaxle, and it actually seems to have made the noise louder. Incidently the transmission shifts fine, and only has a slightly slow 2nd gear synchro.

I have a hard time imagining that this is simply a throw out bearing problem or a pilot bearing problem. Listening with a stethoscope the noise is loudest near the bottom transfer gear and quietest near the top gear-which is the one attached to the throw out bearing.

I'm guessing the problem is with the bottom bearing- the one on the transmission input shaft, or worse yet, in the gearbox itself.

Any thoughts? Anyone?

 

several of my carb 308's have had this weird rattle at idle, warmed up, with the clutch out when they were first delivered to me. ( noise happens as you would be sitting at a traffic light.)

i always change all the fluids in my cars as soon as they are delivered and do the belt service. i also always add 4.5 quarts of gearbox oil, (4 quarts of oil, and a big tube of the GM limited slip additive.) i have used Redline and Swepco 201 gear oils.

i am no expert, but i think the drop gears rattle a bit if there is not enough gear oil in there. i swear with 4 to 4.5 quarts none of the cars made any noise after the gear box oil change.

my QV is the quietest of all of them, but its different in many small ways from the 4 carb 308's i have had so far.

perhaps Steve or Rifledriver will chime in, but it seems to me the rattle may be an indication of not enough gear oil, and at rest, the drop gears are rattling around. on a level surface, the fill to spill method seems to always work as i put that last .5 qt in the gearbox from the top diff fill plug, and quickly re install the lower gearbox fill plug as it comes dribbling out.

 

If the sound goes away when the clutch is depressed it may be bearings inside the transmission. Also, if the sounds is sort of a rotating grinding noise then it is most definitely bearings, but I haven't enough experience to say if this is anything more than just the gears meshing while rotating. I have a little bit of this sound in my gearbox and I have heard this same sound from two other carb 308s so I have written it off as somewhat normal. Any experts want to key in on this?

 

They shouldn't make noise.

 

...or is the oil level being depleted and not replenished fast enough?

 

I suspect drop gear rattle.
Will the noise go away if engine rpms are increased to 1200+rpm (in neutral)?

 

OH? Then why have there been so many complaints for so many years that in the 360 Ferrari finally went to pressed on gears in an attempt to cut some of the noise?

 

You got it.

 

My mondial gear noises came from the middle gear in the bellhousing. Some residu hat tappered an oilhole (green flash). There are also holes in the bearing and bearinghousing that has to be inline (bleu line). My old bearing hat a production failure, it whas'nt put in the right angle to the gear (red flash).

Good luck,
Guido
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If that bearing is the correct part it is fully grooved on the back side so the holes do not need to line up. You had a lubrication problem but it was not caused by the holes not lining up.

 

thanks Brian. I was checking just yesterday on my gearbox noise. It is in fact only when the box is fully warmed up that there is a small amount of noise. this takes quite a bit off my mind

 

The bearing itself whas grooved, but the ring that holds it has a hole that has to be inline with the oilhole (green flash) in the aluminium.

Guido
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