Thank you very much for your input.

Hey Justin,
what scott_ says is on the money...
check the LED indicator on the drive controller and see if it is showing any flash codes. By the way you described the issue though as only temporary (comes and goes) it may not show you anything except during operation.
And as for the controller at the joystick, that is a MIB controller for hydraulics as scott_ said and will not cause any problem like this.
-check your directional and 1A contactors and their tips
-does the drive motor have a clicking sound when driving the machine?
There is a reason i'm asking about the clicking sound...
These motors are pretty good motors but cannot stand much abuse and if they are stalled very much the com bars on the armature can raise up slightly and when they pass by the brushes they will click. If this condition is bad enough it will be fairly loud, when this happens that can make the brushes jump off of the armature commutator and can make it fault out but not remain in that condition if the power is cycled, drive function returned to neutral and then reselected. I have seen this happen many times in these units and others before.

Great thank you very much for the help!!!

What l know this is and older reach if you are standing on the truck by your right leg there is a cover with l think two Allen screws remove the screws and take the cover off in there will be the start contractor and fuses at the bottom is the drive controller might be curtis controller the best way to pull codes is with a hand set connected to the box if not l believe there is a small green light that will blink if there is a fault also that controller only controls the drive circuit if you pull off the top cover where the joy stick is on the right side there is another controller called the nib. board that controls the hyd and also the handle for forward and reverse there will numbers on the board as to what hyd you are working and all switches as far as brake and operater petal if a problem a different number will appear then you can look up number to track down problem. as far as what you are dealing with l believe it is with the drive circuit some codes are just warning codes l think a yellow light will come on for a second on dash. with out hand set you can not see history codes. if hard fault count blinks and look for code.