Clatter in 6th gear

chuckrudd90 · May 21, 2020

1949 JD B - Serial #246578 Trans is quiet in all other gears, but in 6th and under no load there is a very loud clatter. I have not tried it under load as it seems like that is inviting a catastrophic failure. I suspect the clatter is due to broken/missing teeth. Looking for comments on source of clatter and thoughts on whether this is opening up from the top or the side(s). I am not hesitant to open her up, just want to do it the most expedient way.

Side Note: I have been running this same tractor for 53 years now. My dad bought it from an apple orchard in Plattsburg NY when I was 13 years old. Love my tractor!

Thank you,
Chuck

Mike M · May 21, 2020

iirc 4th & 6th are the same gears. Do you notice anything in 4th at all ? Pull the flywheel off and remove the tin cover behind there and you can get a good look at those gears and also see how much play is in the lower countershaft.

MSD · May 21, 2020

Actually its is 5th and 6th that are the same gear.

chuckrudd90 · May 22, 2020

Thanks for the info - will open from the side. It is perfectly quiet in 5th gear, both with and without load. Does that indicate a specific root cause if it is only heard in 6th gear?

MSD · May 22, 2020

When your in 5th gear , your using the lo range shaft. Could be bad bearing on the hi range shaft that shows up when it is turning faster in 6th gear. There's a ball bearing on the end of the top
one and a small roller bearing on the inside of the input shaft. You have to remove that one to fix the ball bearing one so replace it at the same time. Theres also a roller bearing on the input
shaft that I would replace while it is open. The lower shaft has a tapered roller bearing on both ends. You will need to remove the clutch pulley, side cover and shifter rails to get them out. Could be a chipped tooth on the hi-lo gear also. You will have to open it up anyway to find out for sure.

Mike M · May 22, 2020

That does seem weird the noise is not heard in any other gears ? The actual gear is engaged for both speeds only difference being on the other side of the quadrant you go from high range to low or vice versa. And if trouble is in the high low gears or where the upper shaft splits and has a bearing inside the input shaft I would think it should also make noise in other gears ?
Most easy access is to remove the top shifter cover and see if anything obvious shows up ?
You can jack up one side of rear end and rotate it all by hand and even shift it in and out of all the speeds with a pry bar. Just do one at a time or else it will get locked up in two gears at once.

chuckrudd90 · May 23, 2020

Thanks so much for all the info - coming in faster than my pea-brain can properly assimilate. I am halfway through a restoration of my '77 GMC C35 Dually. Was going to change all door and window rubbers, but now have it stripped to bare cab and chassis and doing a complete resto...typical I suppose. I will lay awake nights thinking about the JD tranny job, but won't open it up for at least a month. For sure I will use the info supplied and will come back to this posting once I have found the root cause.

Thank you, Chuck

Mike M · May 23, 2020

In case you do not have it the JD service manual for the late B is a very good manual. I recommend having
one on hand.

Clatter in 6th gear

chuckrudd90

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MSD

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chuckrudd90

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