So i have a '98 machine with the standard Haas 2 speed gear box that will not shift into high gear. I bought this machine used for virtually nothing as the previous owner did not want to rebuild the gear box. When i first powered it up it was in between gears and would not shift into high or low gear. I drilled out the little orifices in the air lines going to the gear box and it imediately shifted into low gear as soon as i hooked up the air. It will try to shift into high gear but the shifter shaft does not fully retract to get high gear fully engaged. It will shift back into low gear with no problem. I also checked that the Mac solenoid valve is working correctly and it is, the air pressure changes from one line to the other when you manually switch the solenoid. I can get it to run in high gear by switching to high gear and then unplugging the high gear micro switch so the control thinks it is fully engaged. But when the spindle runs this way it sounds like the gears are dragging on each other, the RPM is correct so i know its running in high gear. I wouldnt run it this way obviously but i just wanted to know if it was actually in gear or not.
So i guess my question is what is there inside of the gear box that could prevent the gear shifter from being able to fully engage the high gear? I have numerous Haas machines so fixing the gear change problem is nothing new, however i have never had one that will not switch into high gear its always low gear that wont engage.