Toyota Tundra 2005 ext bed car shakes/rattles when accelerating

Hey, Juax. Your problem could be worn u-joints. If you can, crawl up under the truck and try to move the driveshaft around with your hands, if you feel excessive end play your u-joints, or if applicable, hanger bearing could be worn out. Other possible causes of vibration are your tires being out of balance, sticking brake calipers, and worn suspension components. The fact that it stops after you let off the accelerator makes me suspect the u-joints, however. You also said it feels similar to hard shifts and occurs at different speeds. I would also suggest you check your transmission fluid and make sure it’s not low. I hope this helps, good luck!