Noise in transmission

[jinmaman]

I hope someone has an easy solution to this one.

I have a thumping with a very slight rattle noise coming from the driveline of my 224 tractor. It gets louder as the tractor warms up, sounds like it is coming from the front end of the tranny at the creeper box area. It is their when sitting still or moving. I took the creeper plate off to check it out inside and cant see any thing wrong. From what I could see all the teeth were on the gears. The sound goes away when the clutch is pressed. What I did find out is the sound is only there when I put the creeper selector in high as there is no noise when in low creeper. Does this eliminates the clutch as the problem. Therefore it seems to be associated with the creeper high range setting. Other selections like 2 or 4 wheel, different gers ranges or high low range do not effect the noise.

Does any one have any thoughts on what to check next?

 

[jinmaman]

I hope someone has an easy solution to this one.

I have a thumping with a very slight rattle noise coming from the driveline of my 224 tractor. It gets louder as the tractor warms up, sounds like it is coming from the front end of the tranny at the creeper box area. It is their when sitting still or moving. I took the creeper plate off to check it out inside and cant see any thing wrong. From what I could see all the teeth were on the gears. The sound goes away when the clutch is pressed. What I did find out is the sound is only there when I put the creeper selector in high as there is no noise when in low creeper. Does this eliminates the clutch as the problem. Therefore it seems to be associated with the creeper high range setting. Other selections like 2 or 4 wheel, different gers ranges or high low range do not effect the noise.

Does any one have any thoughts on what to check next?

 

[greg_g]

If I understand correctly how it works, you should be able to eliminate the creep gear section. If you had no creeper box, your transmission would be operating in the equivalent of creeper HI. It's only when you move the creeper select lever to LO that the reduction gears are actually engaged. At least that's how I think it works.

You could be hearing the clutch fingers rubbing on the throwout bearing. Pull the bell housing inspection plates and make sure you've got the specified 1mm gap between the three finger tips and the face of the throwout bearing. It also could be the throwout bearing itself - or the pilot bearing - neither of which should go bad on a low hour tractor. Or do you ride the clutch pedal?

//greg//

 

[greg_g]

If I understand correctly how it works, you should be able to eliminate the creep gear section. If you had no creeper box, your transmission would be operating in the equivalent of creeper HI. It's only when you move the creeper select lever to LO that the reduction gears are actually engaged. At least that's how I think it works.

You could be hearing the clutch fingers rubbing on the throwout bearing. Pull the bell housing inspection plates and make sure you've got the specified 1mm gap between the three finger tips and the face of the throwout bearing. It also could be the throwout bearing itself - or the pilot bearing - neither of which should go bad on a low hour tractor. Or do you ride the clutch pedal?

//greg//

 

[RonMar]

As Greg said, creeper high is a straight shaft that passes thru the creeper box and into the main gearbox. Creeper low uncouples this shaft with a sliding collar and connects in the reduction gear.

I had a similar thumping/backlash gear noise on my 284 when new(and still do to some extent). You only really heard it when the clutch was out and the transmission was in neutral. You could still hear it slightly when in gear but not so much since the gearbox was under load(less backlash). What was happening on mine was that there is a considerable ammount of fore/aft slop in the gearbox and the gears on the shaft don't always run perfectly true(not perpendicular to the shaft they are attached to). In some cases there is a little bit of wobble as the gears turn. On mine, when the clutch is let out and the pressure plate grips the disk and spins the creeper input shaft(and PTO shaft), it also pulls the shaft forward slightly(splined clutch disk not slideing freely on the transmission input shaft). This forward movement allowed a gear in the main transmission to move forward slightly. This gear in my tansmission has a little wobble and this brought the edge of it's teeth into contact with the edge of another gears teeth causing a slight thumping sound that would appear more noticeable as the tractor warmed up(thinner fluid, more play). If you remove the main gearbox cover and press the clutch in and out, you will probably see some fore/aft movement of the gears. I first inspected my creeper gearbox and clutch as it also sounded like the noise was comming from up front. When I found nothing unusual, I inspected the main gearbox and ultimatly ran mine in neutral with the main cover removed to try and see what was happening. I was able to determine what was touching to cause the noise. It slings a bit of oil so wear old clothes and safety glasses if you do this.

There was no proper way to fix this, short of complete disassembly and adding shims/thrust washers into the geartrain. In my case it was a fairly minor contact and had mostly "worn-in" and dissappeared by 100 hours.

The mass of the gearbox case transmitted the noise pretty good and made it hard to find the exact location by ear and also made it sound worse than it really was. I would definitly find the source of your noise though as it may not be as minor a problem as mine was.

Also checking the clutch adjustment as Greg suggested is another good practice on a new tractor that may save you headaches down the road.

 

[RonMar]

As Greg said, creeper high is a straight shaft that passes thru the creeper box and into the main gearbox. Creeper low uncouples this shaft with a sliding collar and connects in the reduction gear.

I had a similar thumping/backlash gear noise on my 284 when new(and still do to some extent). You only really heard it when the clutch was out and the transmission was in neutral. You could still hear it slightly when in gear but not so much since the gearbox was under load(less backlash). What was happening on mine was that there is a considerable ammount of fore/aft slop in the gearbox and the gears on the shaft don't always run perfectly true(not perpendicular to the shaft they are attached to). In some cases there is a little bit of wobble as the gears turn. On mine, when the clutch is let out and the pressure plate grips the disk and spins the creeper input shaft(and PTO shaft), it also pulls the shaft forward slightly(splined clutch disk not slideing freely on the transmission input shaft). This forward movement allowed a gear in the main transmission to move forward slightly. This gear in my tansmission has a little wobble and this brought the edge of it's teeth into contact with the edge of another gears teeth causing a slight thumping sound that would appear more noticeable as the tractor warmed up(thinner fluid, more play). If you remove the main gearbox cover and press the clutch in and out, you will probably see some fore/aft movement of the gears. I first inspected my creeper gearbox and clutch as it also sounded like the noise was comming from up front. When I found nothing unusual, I inspected the main gearbox and ultimatly ran mine in neutral with the main cover removed to try and see what was happening. I was able to determine what was touching to cause the noise. It slings a bit of oil so wear old clothes and safety glasses if you do this.

There was no proper way to fix this, short of complete disassembly and adding shims/thrust washers into the geartrain. In my case it was a fairly minor contact and had mostly "worn-in" and dissappeared by 100 hours.

The mass of the gearbox case transmitted the noise pretty good and made it hard to find the exact location by ear and also made it sound worse than it really was. I would definitly find the source of your noise though as it may not be as minor a problem as mine was.

Also checking the clutch adjustment as Greg suggested is another good practice on a new tractor that may save you headaches down the road.

 

[jinmaman]

Good info. Do you know the part number of the gears in question and I will check them out on my parts breakdown. This way I am sure to check the correct one.
Its interesting you said that the trans case may be transfering the sound as I was wondering about this also. I will remove the shift case cover and check it out.
Would it help to reduce the freeplay if a heavier weight oil was used.

 

[jinmaman]

Good info. Do you know the part number of the gears in question and I will check them out on my parts breakdown. This way I am sure to check the correct one.
Its interesting you said that the trans case may be transfering the sound as I was wondering about this also. I will remove the shift case cover and check it out.
Would it help to reduce the freeplay if a heavier weight oil was used.

 

[RonMar]

I will have to look at my manual to get a gear number off the diagram. That particular diagram on John's jinma site dosn't expand so I can't quite make out the numbers(70 something?). The input shaft into the main gearbox is the upper shaft and in my case the one causing the noise was up near the front of the trans. Your's might be a different problem but if it is the same and you take off the main case cover and roll over the gears and work the clutch, you will probably see what I am talking about pretty easilly. As for heavier oil, I don't think it would help much. Things usually take the path of least resistance. Pushing the oil out of the way will probably always be the path of least resistance.

 

[RonMar]

I will have to look at my manual to get a gear number off the diagram. That particular diagram on John's jinma site dosn't expand so I can't quite make out the numbers(70 something?). The input shaft into the main gearbox is the upper shaft and in my case the one causing the noise was up near the front of the trans. Your's might be a different problem but if it is the same and you take off the main case cover and roll over the gears and work the clutch, you will probably see what I am talking about pretty easilly. As for heavier oil, I don't think it would help much. Things usually take the path of least resistance. Pushing the oil out of the way will probably always be the path of least resistance.