I have a 2002 B2300 with only 70K on it. I've had an ongoing issue with the gear shift, it has been worked on 3 times and engine will currently only turn over in neutral. Movement of the shift bar makes a crunchy sound and never really locks into a position. I've had these notes from mechanics over 4 years:

GEAR SHIFTER NOT STAYING IN PLACE
SHIFT CABLE LOOSE AND MISADJUSTED
ADJUSTED SHIFT CABLE FROM UNDER VEHICLE.
SHIFTER NOW GOES INTO ALL GEARS BUT TRUCK SLIPS WHEN IN PARK AND HAS TO BE STARTED IN NEUTRAL
SHIFTER CABLE IS STRETCHED FROM TRANSMISSION TO STEERING COLUMN. A LOT OF PLAY IN SHIFTER ASSEMBLY AS WELL.

Not sure why they keep adjusting rather than replacing the whole gear shifter, or maybe that would cost more than the value of the truck? At this point I want to just sell the Mazda but only if it can be repaired to a safe condition.