I have a 2001 660SJC track boom lift that is having two speed issues. It is the machine that has a steel tracked excavator undercarriage instead of wheels. Runs great in lower speed but doesnt want to go into 2 speed. It will sometimes surge like it goes into 2 speed for a second and then kicks out for a second and back and forth. If I unplug the level sensor it will go into two speed but then it thinks its off level so the boom operates very slow. We tried a new level sensor as it had been leaking but that didn't make any difference. We also checked the position sensors on the boom but they all seem good. Trying to to figure out were the issue is. It seems like it must be a poor connection somewere. TIA