I bought my JD 690E LC a several years ago and have always dreaded moving it any significant distance. From the day I got it, it has very sensitive/jerky track lever/movement control. The forward speed goes from creep to a jerky/lurching movement as the levers/pedals are just increasingly engaged. The only way to smooth out the jerky movement is to fully engage the levers. Then it seems to smooth out but are 'roaring' at full travel speed. As soon as you start to ease back on the levers the jerking starts. which promotes your hands or feet to jerk as well, which creates a jerking amplification. For some reason it's a lot less of an issue, albeit still appears non factory, when going in reverse. I have tried slowing the engine rpm down to try and mitigate the jerky movement, but unless the engine is revved wide open it kills the engine. Which is another concern, as it seems like when engaging the drive levers/pedals to start moving, there is a significant load placed on the engine. I noticed that one of the smaller hoses on the front left front drive planetary appears to have been replaced as it is relatively new. Is there some pilot/pressure circuit that could have air trapped in it that would be causing this? Any guidance would be greatly appreciated.
Welcome to HEF Greg . Machine serial #?
SN# 560821
Do the propel increase speed /decrease speed switches have any affect on the jerkiness or travel speed ?
I ask this assuming that the mode selection is NOT in Precision mode.
I have prior tried to adjusted that propel setting to the tortoise image, and tried the other illuminated button settings directly above it at each of the other positions, but it didn't seem to make any difference. The throttle control via the ECM or main computer was not functional when I 1st got the unit, and I would have to flip the that hydraulic bypass switch to get the engine to rev up to allow using it. I don't know if that controller issue, or deeper issues within the controller are not performing those speed adjustments as well. I eventually converted the throttle control over to a cable control after reading on several websites that was another means to regain throttle control within the cab, versus climbing out to flip that switch back and forth. It sounded like issues with the controller and those functions are fairly common on this generation. Plus the Linde hydraulic actuator that increased the throttle speed developed a significant leak that would continue to leak gallons while the unit was sitting. Since I was told a seal kit was no longer available, disconnected it and capped those hoses. I understand that isn't the 'correct' repair, but appeared to solve two problems. It's jerky behavior has been going on since I 1st got it and while operating in the bypass mode. Part of my rationale for converting over to the manual throttle control was that maybe if I reduced the rpm's on the engine to half throttle or so. The jerky movement would be reduced do to a lower hydraulics pressure. However as prior mentioned on my early post, any attempted movement kills the engine unless it's at full throttle. I don't suppose there is some manual adjustment I can do to duplicate whatever reduced speed control was provided by the controller? As I can live with the slower track speed if it provides smoother track/unit movement...
There is a good possibility your propel lever torsional dampener’s may be worn out.
Sounds like you are stuck in high speed propel. By default most mechanical or electrical issues with the propel control circuit the propel remains in high speed. Try removing the high speed pilot signal to the motors. Remove hose “F“ (in screenshot below) and cap the fitting on the valve block. DO NOT plug the hose but the hose in a pail to capture any oil. Try traveling and post the results.
Diesel Dave has you one the right track. The dampeners give the operator smoother control of the levers and should return to neutral on their own. Have you ever had any issue with throttle control before you went to manual throttle with the button on control panel staying in the idle when trying to select higher rpm?
******* Correction ******* With NO pilot signal to the motors , the motors remain in high speed. A pilot signal is necessary to put the motors in low speed . Remove hose from Port “F” and cap the port. Install hose on port “C”. Port “C “ originally supplied the throttle actuator cylinder. With the system in bypass mode try traveling and post the results .