Can you replace a crankshaft in 1991 Geo Tracker without pulling engine?

No, you cannot realistically replace a crankshaft in a 1991 Geo Tracker (or any car for that matter) without pulling the engine. The crankshaft is a major component deep within the engine block, requiring significant disassembly to access. Even if you could *theoretically* get to it without pulling the engine, the level of difficulty, limited access, and risk of damaging other components would make it far more impractical and likely to result in more damage than simply removing the engine. Removing the engine provides ample workspace and easier access to all necessary parts for a proper crankshaft replacement.