There are loud noises coming from the central area of my 2012 Isuzu D-Max

Any time you have a grinding noise from the driveline of a car, it’s time to have it checked out. That’s because continuing to drive it in that condition might cause more damage than was already there. Grinding sounds from the area of the transmission can indicate worn bearings in the gearbox which, if caught early enough can sometimes be replaced without resorting to a complete transmission replacement. Even so, it will be a big job as the gearbox will need to be removed and pulled apart.

You may also find while you’re inside the transmission that there’s other wear that needs to be addressed, at which point the decision becomes whether to repair or replace. You can buy a reconditioned transmission from a specialist shop, or a second-hand one from what was once called a wrecking yard. If you do the latter, make sure the used gearbox has been tested and comes with some sort of warranty. The cost of a replacement could be anywhere from $1000 to $10,000 depending on what you buy and where you buy it from.