Here's a *general* overview of the steps involved. This is not a comprehensive guide, and you should consult a repair manual specific to your Grand Prix's year and model. Repair manuals are available online and at auto parts stores.
General Steps (Consult your repair manual for specifics):
1. Safety First: Disconnect the negative battery terminal. Support the vehicle securely on jack stands. Wear safety glasses and gloves.
2. Drain Fluids: Drain the transmission fluid completely.
3. Disconnect Components: Disconnect the driveshaft, shift linkage, electrical connectors, cooling lines, and any other components connected to the transmission. This will vary greatly depending on your year and model.
4. Remove the Transmission Mount(s): These bolts secure the transmission to the vehicle's frame.
5. Support the Transmission: Use a transmission jack to support the transmission's weight as you disconnect it from the engine.
6. Separate Transmission and Engine: Carefully separate the transmission from the engine. This often involves removing the bellhousing bolts.
7. Lower the Transmission: Slowly lower the transmission using the transmission jack.
Tools You'll Likely Need:
* Jack and jack stands
* Transmission jack
* Socket set (various sizes)
* Wrenches (various sizes)
* Torque wrench
* Pry bar (possibly)
* Drain pan
* Repair manual specific to your vehicle
Again, this is a highly simplified overview. Improperly removing a transmission can cause significant damage to your vehicle. If you lack the experience or tools, it is strongly recommended to take your Grand Prix to a qualified mechanic. The cost of professional repair will likely be less than the cost of fixing mistakes made during a DIY attempt.