4 replies to this topic

[JimmyStinkpickle]

Before I start tearing things apart, can someone please help me identify this high pitched rattling noise when I am reversing? It kind of sounds like a loose bearing tumbling around. I can also hear it going forward but it's more intermittent, not quite as loud, and it's accompanied by an occasional chirping noise. There is no noise when coasting in neutral and the gearbox and clutch seem to be working fine. I put the car on jack stands and ran it in reverse to pinpoint the noise. It seems to be coming from an area around the pot joint and differential on the right hand side. I've included some video links for reference. Has anyone heard a sound similar to this? Any ideas what it could be? I recently replaced both diff oil seals and didn't notice anything unusual (the noise was present before they were replaced). There is a nominal amount of play when pushing/pulling on the driveshafts. It's a 1275 MKIII Cooper S. Any help/advice would be greatly appreciated!

 

https://youtu.be/oUX1575efBg

 

https://youtu.be/--iiGWC3sZA

 

 

[Spider]

A little hard to pin point for sure but it sounds like the Mainshaft Bearing has collapsed.

Regardless, the Engine needs to come out and Gearbox off to be sure.

 

I would suggest you cease driving it as part of the Pinion Gear make want to come through the Case.

[JimmyStinkpickle]

A little hard to pin point for sure but it sounds like the Mainshaft Bearing has collapsed.

Regardless, the Engine needs to come out and Gearbox off to be sure.

 

I would suggest you cease driving it as part of the Pinion Gear make want to come through the Case.

 

Thanks Spider. I was afraid it was something that involved removing the engine. What would cause the main shaft bearing to fail? Anything else I should look out for after I remove the gearbox?

[Spider]

 

What would cause the main shaft bearing to fail? Anything else I should look out for after I remove the gearbox?

 

 

Yes, no one likes that kind of news. Hard to say why it may have failed, but I have seen quite a few over the years. The Oil in these cars isn't as clean as it could / should be due to the Gearbox, it has Baulk Rings that because of the way they work, they do wear off metallic material that can be damaging to Bearings and Oil Pumps, most eventually gets caught on the Magnet on the Sump Plug, but it can take a while to get there.

 

Anything else to look for ? If it were me, I'd completely overhaul the Gearbox. Usually, once one part of the Gearbox shows high wear, the rest isn't too far behind. The other item I'd replace is the Oil Pump.
 

[JimmyStinkpickle]

Yikes. Drained the oil and chunks of metal came tumbling out of the sump. Definitely looks like the remains of a ball bearing cage. Not sure if it's the third motion shaft bearing or one of the diff bearings? In any case, the motor is being pulled this week for a gearbox refurb. I hope everything goes smoothly. (It won't)

 

https://i.ibb.co/bsMRGDm/IMG-2643.jpg

 

https://i.ibb.co/XbqH4RL/IMG-2645.jpg

 

https://i.ibb.co/yFKyWwm/IMG-2649.jpg

Edited by JimmyStinkpickle, 11 May 2022 - 04:26 AM.