Transmission input shaft?

Laslonimne

Laslonimne

Member
When engaging or disengaging the clutch on my 1947 Cub, I get a chatter-or rattle. Once in gear there is no noise and everything works fine as I mow with my pto-driven Pennington mower.
I suspect the input shaft is the source of the noise.
Any advice would be most welcome.
D
 
Laslonimne said:
When engaging or disengaging the clutch on my 1947 Cub, I get a chatter-or rattle. Once in gear there is no noise and everything works fine as I mow with my pto-driven Pennington mower.
I suspect the input shaft is the source of the noise.
Any advice would be most welcome.
D
Click to expand...
Have you looked at the throw-out bearing to see how worn it may be?
 
Laslonimne said:
Any advice would be most welcome.
Click to expand...
Hi,
The long shaft from the clutch to the transmission stops turning when you push the clutch pedal down, so the shaft wouldn't make any noise when stopped.
It could be the clutch. If it makes a grinding, or metal to metal noise when you push the pedal all the way down, and you feel it in the pedal, the pressure plate finger height may be too low, and need adjusting, or raising up some, a common thing on Cubs.
If that is happening, the metal of the throwout bearing, or the throwout bearing holder hits on the turning pressure plate. Don't push the pedal down to where the noise happens, it can damage the clutch.

Below is a page from the 1947 Cub owner's manual showing adjusting the clutch pedal free play. There is a picture of the clutch lower on the page, you can see 1 of the fingers in the picture. There are 3 fingers. You have to get under the Cub, and look in through the hole under the clutch housing to see the throwout bearing, or fingers. Use a light. The hole originally has a cover.
The original style throwout bearing has graphite material, and doesn't turn. They can wear down from use. The material originally sticks out of the metal part of it 5/16".
https://farmallcub.club/rudi/farmallcub.com/rudi_cub/www.cleancomputes.com/Cub/Cub%20Owner's%20Manuals/McCormick-Deering%20Farmall%20Cub%20Owner's%20Manual%205-23-47/Page-40.jpg

IH changed the method of adjusting the pedal free play during 1948, so if your Cub is newer than that, it would be different than this manual shows.
Below is a picture of a new Cub throwout bearing. :)
 

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disconnect the mower belt see if the noise is still there, make sure mower pulley is tight on the shaft
 
Bill: Clutch and throwout bearing are just a few years old. Throwout bearing is lubed annually and looks/feels fine.

Glen: The noise goes away when the clutch is full depressed and when the clutch is fully released.

tst: The noise is the same whether the PTO is engaged or not. but the mower pulley on the PTO shaft is tight.

Thanks for the recommendations. I might add that I feel a bit of vibration in my seat, but not my foot, when there is a rattle.
 
That may be a pilot bushing gone south. That’s the way Cubota acted when the custom made bushing failed. I did a little more machine work so a stock bushing would fit. Problem solved.
 
We’ve determined the shaft is slightly bent near the middle. I plan to continue mowing through the summer and replace it in the Fall. I’ll also replace all the bearings and bushings in the transmission and PTO at that time.
 
Don’t forget the bushing in the reverse idler if you’re rebuilding transmission. That can help cause the Cub gear chatter. Also, that little shaft gets worn reverse gear runs on. Not a big deal for a machine shop to make one. It’s pretty simple.
 
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