* Year: 10-bolt rearends were used across many years, and their design and component strength changed over time. Earlier versions are generally weaker than later ones. Some later models were beefed up significantly.
* Application: A 10-bolt from a light-duty pickup truck will be significantly weaker than one from a heavier-duty truck or a performance car. Even within a similar vehicle, different options (e.g., axles, gears) affect the overall strength.
* Modifications: Modifications like aftermarket axles, stronger gears, and posi-traction units can greatly increase the strength. Conversely, worn or damaged components significantly reduce strength.
* Specific components: Axle shafts, gears, and the differential case itself all contribute to the overall strength. A weak point in any one of these components limits the overall capability.
In short, there's no single answer. A stock, early model 10-bolt in a light-duty application might be easily broken with moderate power or abuse. A later model, properly upgraded 10-bolt can handle considerable power, but it's still generally considered weaker than a 12-bolt or other heavier-duty rear ends commonly found in performance vehicles and heavier trucks.
If you're trying to determine the strength of a specific 10-bolt, you need to identify the year, application, and any modifications it has undergone. Even then, it's difficult to give a precise number for how much torque or horsepower it can reliably handle. Many resources online discuss the limitations and potential upgrades for different versions of the 10-bolt.
