Before working through common leak sources, clean your Troy Bilt snow blower's engine as thoroughly as possible. Getting rid of excess oil makes finding the leak easier. Use a shop rag to get most of the oil off, and use small engine cleaner to remove any caked-on grease or debris.
Check your Troy Bilt snow blower's oil filter. This is a common source of oil leaks in small engines, and it is a relatively easy fix. Replace the faulty oil filter, making sure to install the new filter properly, according to your user manual. Check whether the leak issue has been resolved.
Many Troy Bilt snow blowers come with a small oil plug that can be removed to drain the unit of oil during routine maintenance. Over time, this plug can become loosened or damaged, and that can lead to leaks. Check the plug for signs of damage, and tighten it down as per the instructions in your user manual. Turn the blower on and note whether the leak persists. If necessary, replace the plug with a certified Troy Bilt replacement part.
Removing and replacing crankshaft seals and other engine gaskets may be too difficult a task for you to attempt. Tighten down all bolts and nuts on the engine, and, if the leak persists, consider contacting an authorized Troy Bilt service center. The service representatives are better equipped to disassemble the engine and repair the unit.