2006 3640 E makes knocking noise

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3640 E

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The knocking sound is not coming from the engins and everything seems tight when I raised the cab and checked the hydrstat drive. Any guess as to what it could be? doesn't seem as bad at higher RPM.
 
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3640 E

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I was told it could be where the hydrostat bolts to the fly wheel. Does this sound likely? I have never done maitnenance on a machine like this, is this difficult to get at? There is a plate in the back of the compartment where the hydrostat is, is it behind this plate?
 

Tazza

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I was told it could be where the hydrostat bolts to the fly wheel. Does this sound likely? I have never done maitnenance on a machine like this, is this difficult to get at? There is a plate in the back of the compartment where the hydrostat is, is it behind this plate?
I guess it is possible. I have never worked on one so i don't know how they join the pump to the motor. If it has a U-joint, it could be failing.
How can you be sure the knock isn't the engine?
Could it be a cooling fan? or pulley that is wobbling?
 
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3640 E

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I guess it is possible. I have never worked on one so i don't know how they join the pump to the motor. If it has a U-joint, it could be failing.
How can you be sure the knock isn't the engine?
Could it be a cooling fan? or pulley that is wobbling?
When I open the back door where the engine is the engine sounds fine, radiator and fan seem to be fine too, overflow bottle is cracked and needs replaced. The noise seems to be coming from underneath the cab where the hydraulics are. I believe the hydrostat bolts directly to the flywheel. I bought this machine recently, it has 3800 hours on it, is extremely filthy, and looks really roughed up but engine seems to run fine and all functions seem to work fine. The only thing missing are the lines and hook ups for attachments, but I don't think those would be too expensive to replace.
 

Tazza

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When I open the back door where the engine is the engine sounds fine, radiator and fan seem to be fine too, overflow bottle is cracked and needs replaced. The noise seems to be coming from underneath the cab where the hydraulics are. I believe the hydrostat bolts directly to the flywheel. I bought this machine recently, it has 3800 hours on it, is extremely filthy, and looks really roughed up but engine seems to run fine and all functions seem to work fine. The only thing missing are the lines and hook ups for attachments, but I don't think those would be too expensive to replace.
Checking all the mounting bolts from the engine to the pump is a good start, anything loose will make noise.
Really not sure what else could be around there causing the noise.
 
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3640 E

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Checking all the mounting bolts from the engine to the pump is a good start, anything loose will make noise.
Really not sure what else could be around there causing the noise.
Spent Friday, Saturday, and Sunday cleaning and checking everything out on "Puddles" that is what I have named the skid steer since every time I park her for a while she leaves a little puddle of some type of skid steer fluid!! I believe I have found the nocking noise, it is the hydrostat but not due to a problem with the hydraulic pump itself but some GENIUS welded a piece of flat stock between one of the motor mounts and the body of the machine instead of replacing worn motor mounts. I believe this is now transfering engine vibration to the hydrostat and making it jump up and down wildly. I can hold down on the hydrostat when it is making the knocking sound and it goes away. Now all I have to do is cut the piece of flat stock and I'm going to change ALL the motor mounts and I believe she will be good as new and no more knocking!! Not sure how difficult changing the motor mounts is going to be yet but there doesn't look like there is much room in there to work.
 

Tazza

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Spent Friday, Saturday, and Sunday cleaning and checking everything out on "Puddles" that is what I have named the skid steer since every time I park her for a while she leaves a little puddle of some type of skid steer fluid!! I believe I have found the nocking noise, it is the hydrostat but not due to a problem with the hydraulic pump itself but some GENIUS welded a piece of flat stock between one of the motor mounts and the body of the machine instead of replacing worn motor mounts. I believe this is now transfering engine vibration to the hydrostat and making it jump up and down wildly. I can hold down on the hydrostat when it is making the knocking sound and it goes away. Now all I have to do is cut the piece of flat stock and I'm going to change ALL the motor mounts and I believe she will be good as new and no more knocking!! Not sure how difficult changing the motor mounts is going to be yet but there doesn't look like there is much room in there to work.
Wow, that is rather dodgy to say the least. The mounts are there to absorb the vibrations and prevent damage from these vibrations. Not sure the previous owner has a lot of thought before doing that modification. Glad you found it though, hopefully no damage was done by this.
I love the name, so very fitting. I have a few names for my gear too:
Welder - Mr sparky
Plasma cutter - Mr Burns (for obvious reasons, every time i use it, i get burnt...)
The sand blaster - Sandy
Bobcat - Bob
Sadly, there wasn't a great deal of imagination that went into the naming....
 
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3640 E

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Wow, that is rather dodgy to say the least. The mounts are there to absorb the vibrations and prevent damage from these vibrations. Not sure the previous owner has a lot of thought before doing that modification. Glad you found it though, hopefully no damage was done by this.
I love the name, so very fitting. I have a few names for my gear too:
Welder - Mr sparky
Plasma cutter - Mr Burns (for obvious reasons, every time i use it, i get burnt...)
The sand blaster - Sandy
Bobcat - Bob
Sadly, there wasn't a great deal of imagination that went into the naming....
Yeah, I am not a mechanic but I definitely know better than to do something like that. I am just a little concerned about how difficult changing the motor mount isolators is going to be. I will be doing it myself and I am an extremely determined person and will stay after it until I figure it out.
 

Tazza

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Yeah, I am not a mechanic but I definitely know better than to do something like that. I am just a little concerned about how difficult changing the motor mount isolators is going to be. I will be doing it myself and I am an extremely determined person and will stay after it until I figure it out.
Access is generally the biggest issue. In the past i have banaged to do the hard to access mounts by removing the bolts and using bars to lift the pump/motor up to slide the new one into place. Hopefully you will have a little room to do the same.
 
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