Instead, there's a fill plug. It's usually a small bolt or plug near the top of the transmission. It's important to consult your 1997 Pontiac Transport owner's manual for the precise location. The manual will show diagrams and clearly identify the fill plug.
Without the owner's manual, I strongly advise against attempting to add transmission fluid yourself. Incorrectly adding fluid can cause serious damage to the transmission. It's best to take your vehicle to a qualified mechanic for transmission fluid service.
