Ok guys, I've been fixing & running heavy equipment for decades, but this has me stumped. Bought a 2007 256C 4 years ago. It now has 8K+ hrs. Last year it started jerking badly going forward or backwards like the wheel motors are out of sync. Dealer is no help, they want thousands to diagnose a problem that the C models have had for years. They have obviously fixed this problem in the D's...
The machine is a 2 speed with the creeper gear as well. I'm the second owner, Kiewit owned it before me and put 7300+ hours on it.
So here are the clues:
-When machine is cold, operates fine
- After it warms up, summer - 10 minutes, winter in Colorado 30-60 min. Machine will start to jerk side to side to where a guy can't do anything with it in close quarters safely.
- If you push a pile and raise up the loader arms halfway and try to move the machine, it'll throw a fit sometimes and not move or be able to lower the loader at all. Especially when the bucket is down as in using the teeth vertically to spread material. Only option then is to center the drive (left) joystick, then try and lower the arms before moving the machine. Sometimes this throws a code, sometimes not.
- It's like the drive motor on one side ( I think the left) is out pacing the right side.
-BUT, the really weird part is this. I first noticed this in creeper gear running a trencher. It has gotten progressively worse to where it happens in low gear as well. If I kick it into high gear, it goes away completely. Creeper gear is certainly worse than low gear, high gear is perfect. Sometimes this throws a code, sometimes not.
- Cat had a joystick recall on this machine and it was not done before I got it. I have replaced the left (drive) joystick and had dealer calibrate it.
- I have codes 2687-8, 2688-8, 2685-8, 2686-8...Left & right side sensors. But like I said, it does not always throw a code on me.
3+ decades of running all kinds of heavy equipment, I'd almost say a pressure relief valve is misbehaving after it gets warm. Sure seems like a hydraulic flow issue versus this fly by wire contraption that Cat came up with. I don't have the scanner to go through the electronics and certainly don't want to spend the dollars the stealer wants me to spend.
Anybody know what happens when you kick it into high range and why that would solve the issue?
Any ideas?
Anybody dealt with this and have a solution?
Thanks.
The machine is a 2 speed with the creeper gear as well. I'm the second owner, Kiewit owned it before me and put 7300+ hours on it.
So here are the clues:
-When machine is cold, operates fine
- After it warms up, summer - 10 minutes, winter in Colorado 30-60 min. Machine will start to jerk side to side to where a guy can't do anything with it in close quarters safely.
- If you push a pile and raise up the loader arms halfway and try to move the machine, it'll throw a fit sometimes and not move or be able to lower the loader at all. Especially when the bucket is down as in using the teeth vertically to spread material. Only option then is to center the drive (left) joystick, then try and lower the arms before moving the machine. Sometimes this throws a code, sometimes not.
- It's like the drive motor on one side ( I think the left) is out pacing the right side.
-BUT, the really weird part is this. I first noticed this in creeper gear running a trencher. It has gotten progressively worse to where it happens in low gear as well. If I kick it into high gear, it goes away completely. Creeper gear is certainly worse than low gear, high gear is perfect. Sometimes this throws a code, sometimes not.
- Cat had a joystick recall on this machine and it was not done before I got it. I have replaced the left (drive) joystick and had dealer calibrate it.
- I have codes 2687-8, 2688-8, 2685-8, 2686-8...Left & right side sensors. But like I said, it does not always throw a code on me.
3+ decades of running all kinds of heavy equipment, I'd almost say a pressure relief valve is misbehaving after it gets warm. Sure seems like a hydraulic flow issue versus this fly by wire contraption that Cat came up with. I don't have the scanner to go through the electronics and certainly don't want to spend the dollars the stealer wants me to spend.
Anybody know what happens when you kick it into high range and why that would solve the issue?
Any ideas?
Anybody dealt with this and have a solution?
Thanks.
