Noise in transmission

   / Noise in transmission #11  
Hopefully you don't have anything metal circulating around in the gear oil, cuz it can destroy a gearset in a heartbeat. I know, I had to rebuild a transfer case already. But possibly the clunk is your transfer case arbitrarily disconnecting from the (front) driveshaft. That equates to the tractor jumping out of 4wd. Since 2wd (rear) is a constant, there's no "neutral" in between like with the gearshift or shuttle levers. It jumps straight from 4wd to 2wd, and the sound of the disconnect under load could be described as a "clunk"

//greg//
 
   / Noise in transmission
  • Thread Starter
#12  
Wow you know that might be a possibility Greg because I'm having trouble with the 2 to 4 wheel shift lever beside me. Maybe it is popping in and out on the fly?? I was trying to adjust that lever underneath to no prevail because it seems like and can't shift from 4 to 2 properly or visa versa. Front tires skid when I put it in gear that's how I know that it is in 4 wheel. Could you elaborate on this Greg a bit. Again, good thinking!!

Thanks

Cory
 
   / Noise in transmission #13  
Well, my KM454 would pop outa 4wd regularly. I'd look down, and find the lever had moved itself from 4wd to 2wd. But mine did it without the noise. At some point later, the lever finally stuck in 2wd. Usually I could get it working again by manually rocking one of the front tires while working the lever. That trick didn't work this time.

So I pulled the cover plate to see what I'd find. The sliding fork was definitely not moving, so I put the front tires up in the air again. Then while rocking a front tire, I tried moving the fork. This worked, and I was able to move the fork by hand between 2wd and 4wd. I cleaned the gasket and replaced the cover plate. Don't ask me why this worked, but the lever has worked freely ever since - and no longer pops out of 4wd either. But clearly something was binding, and something in that process I just described must have "unbound" it. Not very scientific, but that's the best I can do.

//greg//
 
   / Noise in transmission #14  
Since you are new to Chinese Tractors here is what I have found working with 2 of them I have used. The 4x4 is easily engage while rolling and even making a slight turn seems to help. Trying to engage and dis-engage was tough when not moving.

The same is true for the diff locks on both.

Chris
 
   / Noise in transmission #15  
Since you are new to Chinese Tractors here is what I have found working with 2 of them I have used. The 4x4 is easily engage while rolling and even making a slight turn seems to help. Trying to engage and dis-engage was tough when not moving.

The same is true for the diff locks on both.

Chris

Not sure about the Foton, but on my Jinma, the 4X4 and Differential lock mechanisms are two flat faced "pawl" devices that slide together and interlock. The pawl lookes basically like a 6 piece pie with every other piece missing. If you put two of these together, the 3 triangular pieces/teeth on one pawl will fit into the space between the 3 teeth on the other pawl. Because they are flat faced, they must be perfectly aligned before they will slide together. Like Chris said, rolling helps engage them, in fact, it is almost always a necessity, unless the teeth just happen to be in alignment when you pull on the 4X4 lever. To engage 4X4 or the difflock, while rolling(or with a rear wheel spinning:)), I apply gentle pressure to the control lever, and eventually the teeth align, and it falls right into 4X4 or difflock. Comming out of 4X4 is easy, just put some pressure on the lever, and it may come out easlly, depending if the pawl drive is under load at that moment. If it is stiff disengaging going forward, try it while rolling backward... For the difflock, I almost always have to turn the tractor from right to left to unload the difflock pawls so the spring will dissconnect them...

If the foton uses the same mechanism for 4X4 or difflock, I doubt it is making your noise, as it takes a little bit of travel and some applied force to engage/disengage, and I doubt that input happening by itself.

Can you determine if it happens in 2 or 4 wheel drive? that might help eliminate the transfer case or driveshaft... If yours is like most of these chinese tractors, it is probably dead easy to pull the top covers and expose most of the forward gearbox for a visual examination. The rear differential and PTO gearbox is probably another story:( A mechanics retrival magnet on a flexible handle is good for pushing down around the sides of the gears looking for any metal lying loose in the sump below the gears. You could have a broken piece of shift fork dancing around in there, occasionally falling against a spinning gear and being whacked out of the way by a gear tooth for it's trouble. Roll the gears over slowly by hand(will need to jack up a rear wheel, and or push in the clutch for this) looking for chipped gear teeth.

Better to find this sooner than later. As Greg mentioned, a stray piece of metal finding it's way into the wrong place will destroy a gearbox is short order...
 
   / Noise in transmission
  • Thread Starter
#16  
Good points here everyone, I'm about to install my overflow container and take a closer look at this drive system to see what I can find.

Cory
 
   / Noise in transmission
  • Thread Starter
#17  
Didn't open up the transfer case yet but I figured out the trick to move from 4 to 2 to 4 wheel drive. Just like everyone here said you have to have the tractor crawling a bit with the clutch in and it will shift very easily! Now I did some more mowing here with the unit in 2 wheel drive and I still heard the rattle or clunk just below me but not as frequent; more noticeable on a bumpy area. It is also there without the PTO driven which I remember as well. I'm now thinking worst case scenario that something is loose in there and I've been lucky so far. I'm not sure where to open up the unit yet but I'll have a closer look now. Any pictures or explanations would be much appreciated as always.

Thanks

Cory
 
   / Noise in transmission #18  
When you say the noise is more noticeable on bumpy areas it makes me think that there may be something loose that is shifting on the bumps.

My tractor developed an oil leak that was the result of the flywheel housing not being properly bolted to the block at the factory. Something similar could be causing your "clunk." Check all the transmission, axle housing, bell housing and other bolts for tightness. If something is loose enough to shift around it will inevitably end up being a worse problem if left un-fixed.

Rich
 
   / Noise in transmission #19  
Didn't open up the transfer case yet but I figured out the trick to move from 4 to 2 to 4 wheel drive. Just like everyone here said you have to have the tractor crawling a bit with the clutch in and it will shift very easily!

You don't need the clutch to shift between 2 and 4 wheel drive on pretty much any 4X4 vehicle with engaged/locked hubs. The clutch only disconnects the engine from the transmission input shaft. The transfer case gets coupled into the transmission way back near the transmission output. When rolling, the front wheels are driving the front axle/diff, drive shaft and transfer case. The rear axle/diff/wheels are driving/being driven by the transmission output. When rolling, the 2 parts that couple together for 4X4 are rotating at nearly the same speed regardless of where the clutch pedal is. Just pull on the lever while driving, when the pawls align, it will fall into place. When disengaged, the pawls rotate at a slightly different speed due to gearing and tire differences between front and rear axle. Because of this, you only want to use 4WD on soft surfaces where the tires can slip. No slip, means extra transmission wear or something breaking

Now I did some more mowing here with the unit in 2 wheel drive and I still heard the rattle or clunk just below me but not as frequent; more noticeable on a bumpy area. It is also there without the PTO driven which I remember as well.

Dose it make the noise with the mower removed driving over the same terrain at the same speed? These cast iron transmission housings conduct noises pretty well. It could be the mower shifting/bumping thru the 3 point hitch...

I'm now thinking worst case scenario that something is loose in there and I've been lucky so far. I'm not sure where to open up the unit yet but I'll have a closer look now. Any pictures or explanations would be much appreciated as always.
Thanks
Cory

Cory, like I said, I am not specifically familliar with your tractor, but it is probably similar to most of these I have seen. Between your legs when seated are several gear levers for main transmission(1,2,3,R), Hi-Lo speed, Creeper and 2-4WD. Some of these levers may go in thru the side of the case(my 4WD lever does). The majority of the control levers probably go into cover plates that have 6 to 10 bolts holding them in place on top of the transmission case. You should be able to remove those bolts with a socket and lift the cover and it's lever up and away to look inside the gearboxes. Just note where the lever is located when you lift the plate clear, such as first gear, high range and creeper gear disengaged. Once you lift a cover plate up, it should be pretty easy to see where the underside of the lever needs to be returned to when you re-install the cover plate.
 
   / Noise in transmission
  • Thread Starter
#20  
Yeh, it's the same thing without the pto so I'm going to take the advise seriously even though I don't want to open up the tranny, I'm going to anyway to make sure I don't damage it.

Thanks

Cory
 
 
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