* Automatic Transmission: The fill location is usually on the side of the transmission case itself. It's often a dipstick-like tube with a cap. You might find it on the passenger side, but it's not consistently located in the same spot across all models. Look closely at the transmission case; the filler tube will likely be clearly marked. If you can't locate it visually, consult a repair manual specific to your Lemans's year, model, and transmission type (e.g., Turbo Hydra-matic 350, Turbo Hydra-matic 400).
* Manual Transmission: Manual transmissions generally don't have a dipstick. They are filled through a specific fill plug on the transmission case. Again, a repair manual for your specific vehicle is crucial to determine the exact location. You'll likely need to get under the car to access it.
Warning: Without a repair manual or access to a diagram for your specific 1972 Pontiac Lemans' transmission, attempting to add transmission fluid is risky. You could easily overfill or add fluid to the wrong location, causing serious damage to your transmission. A repair manual will give you diagrams and specific instructions. Consider consulting a mechanic if you are unsure.
