* Automatic Transmission: If it has an automatic transmission (most common), it will likely require approximately 3-4 quarts of fluid for a complete change. However, it's crucial to check your owner's manual for the exact amount specified by Ford for your particular vehicle's transmission. Some procedures recommend a series of partial changes to more completely replace the fluid.
* Manual Transmission: If it's a manual transmission, the amount will be less, likely closer to 2 quarts but again, you *must* consult the owner's manual for the exact amount.
Do not rely on a general answer. Always refer to your owner's manual for the precise transmission fluid capacity and type for your specific 1991 Ford Explorer.
