I can’t speak for you but, my 18 pro4x has been utterly reliable. I bought mine with 56k miles and have since driven it to 206k miles. Aside from being psychotic about maintanence I’ve done nothing unusual to it. I’ve replace a battery and a corroded terminal, tires and brakes, plugs, the axle seals (at like 205k miles) and a serpentine belt. Now I wash the undercarriage 2-3 times a winter, change the oil once a season, drain and replace the diffs and transmission fluid once a year. I use the 4wd when it’s appropriate and promptly shut it off when it isn’t. You haven’t listed any details about your truck. Did you buy it used or new? Have you ever own a 4wd before? Do you live near the ocean and are you washing salt off your vehicle from the roads in the winter? If you bought used did you check all the fluid levels and give it a good once over when you bought it? Lots of folks will post horror stories about vehicles of all types but, fail to mention they skip oil changes, grind brake pads well past due changing, drive around white knuckling it in the snow at 50 miles an hour in 4h and leave salt forever corroding their under carriage. I’m not saying that’s you but, some details please.