why do my truck make a ticking noise and show 0 for the oil but it have oil in t

Do you mean the oil pressure guage reads zero? you may have a serious issue here, first you need to find out if your oil is circulating, you may have an oil pump problem, some early 5.7l engines had an issue where the pick up tube would fall out of the engine into the bottom of the oil pan, not sure if you have this model..also your oilpressure sender may be faulty. Seek a mechanic that can confirm oil pressure they have a test for this, but if the vehicle is ticking alot dont drive it you will cause a lot of damage to the engine if there is no oil pressure..