I have a Mazda B2500 from the late 90s - early 2000s. It will not move forward in drive, but it will move in either reverse, 2nd gear or 1st gear. Is it safe to be consistently driving in 2nd or 1st gear? And what could be the possible issue for this?
By 2nd gear and 1st gear, I assume you are referring to the low-gear position on the shifter. It is perfectly fine to drive in those, as long as your revs aren't getting too high.
If the low-gear position work but the drive position does not, I would assume you need an adjustment to your transmission shift cable.