What cause a rear end to go out?

A rear end, or rear differential, can fail due to several factors, including lack of proper lubrication, overheating, or excessive wear from age and use. Contaminated or old gear oil can lead to insufficient lubrication, causing components to grind and wear down. Additionally, mechanical issues such as broken gears, worn bearings, or improper alignment can also contribute to failure. Regular maintenance and timely fluid changes are essential to prevent rear end problems.