The 1998 Chevy Venture uses
Dexron III automatic transmission fluid. However, it's crucial to double-check your owner's manual. While Dexron III is commonly recommended for this year and model, GM sometimes made changes, and your specific transmission might have different requirements. The owner's manual will definitively state the correct fluid type.
If you can't locate your owner's manual, you can often find a digital version online through the Chevrolet website or a reputable parts website using your VIN.