To find the transmission type:
1. Check your owner's manual: This is the most reliable source.
2. Look for a tag on the transmission itself: This might be difficult to access without some mechanical knowledge.
3. Check your vehicle identification number (VIN): A VIN decoder (many are available online) can tell you the transmission type based on the VIN.
Once you know the transmission type, you can search online (e.g., Google) for "[Transmission type] fluid capacity 1998 Chevy Silverado" to find the correct amount. You should also find information about the type of transmission fluid to use.