1956-1972 Buick Century Automatic Transmission Mount Replacement Guide
Learn to identify a failing transmission mount in your classic Century and understand your replacement options.
- A loud clunk when shifting into gear is the number one symptom of a failed transmission mount.
- Aftermarket polyurethane mounts (like those from Lakewood) offer high durability but will increase cabin vibration compared to stock rubber.
- Fitment is critical. The 1956-1972 period covers many Buick designs; you must verify the part fits your specific year and transmission.
- Replacement is a straightforward DIY job for most classic car owners with basic tools.
Symptoms of a Failing Transmission Mount
A worn-out transmission mount on a classic car like the Buick Century will make its presence known. You should suspect a bad mount if you notice any of these signs:
- Clunking or Banging Noises: The most common symptom is a loud clunk or bang when you shift from Park into Drive or Reverse. You may also hear it during hard acceleration. This noise is the transmission physically moving and hitting the frame.
- Excessive Vibration: If the rubber or polyurethane in the mount is worn, it can no longer absorb drivetrain vibrations. You'll feel this as a new or worsening vibration in the floor, seats, or even the steering wheel, especially when idling or accelerating.
- Visible Drivetrain Movement: With the vehicle safely secured, you can often see the engine and transmission lurch excessively when shifting gears. This is a clear sign the mount is no longer holding the assembly securely.
Choosing the Right Aftermarket Mount
For a vehicle from this era, "new OEM" parts are generally not available. Your options are typically New Old Stock (NOS), used parts, or new aftermarket parts. Since used mounts are not recommended, most owners will choose a new aftermarket part.
Fitment is Not Universal
The 1956-1972 Buick Century covers several different body styles, chassis designs, and transmission options. A single transmission mount will NOT fit all vehicles in this range. It is critical to verify that any part you order is correct for your specific year, model, and transmission type (e.g., Dynaflow, TH400). Always check the part's application list.
Standard vs. Performance Mounts
The main choice in the aftermarket is between a standard rubber mount and a performance polyurethane mount.
- Standard Rubber Mounts: These are designed to mimic the original factory part. They are soft and provide the best vibration absorption for a comfortable, quiet ride. However, the rubber can degrade over time from heat and fluids.
- Performance Polyurethane Mounts: Brands like Lakewood offer heavy-duty polyurethane mounts. Polyurethane is a much stiffer material that is more durable and better at controlling drivetrain torque, which is ideal for performance applications. The main trade-off is that polyurethane transmits more noise and vibration into the cabin compared to rubber. If your priority is performance and durability, polyurethane is a great choice; if you want a stock, smooth ride, a rubber mount is better.
| Part Type | Estimated Cost (Part Only) |
|---|---|
| New Old Stock (NOS) | $75 - $200+ (if found) |
| New Aftermarket (Standard Rubber) | $25 - $50 |
| New Aftermarket (Lakewood Polyurethane) | $40 - $70 |
| Shop Labor | $100 - $250 |
Frequently Asked Questions (FAQ)
How do I know for sure if my transmission mount is bad?
Aside from the symptoms of noise and vibration, a visual inspection can often confirm the problem. Look for deep cracks, separated rubber, or signs that the mount has collapsed. A mechanic can safely test for excessive movement to be certain.
What is the difference between a rubber and a polyurethane mount?
Rubber is softer and better at absorbing vibration for a comfortable ride. Polyurethane is a harder, more durable plastic that excels at controlling engine and transmission movement, but it will transfer more vibration into the car's cabin.
Will a Lakewood polyurethane mount make my classic Buick vibrate?
Yes, you will likely feel more vibration and hear more drivetrain noise with a polyurethane mount compared to a factory-style rubber one. This is a known trade-off for the added durability and performance. For a street-driven car where comfort is key, many owners prefer to stick with rubber.
Can I replace the transmission mount myself?
Yes, for a classic rear-wheel-drive car like the Century, this is a very manageable job for a DIY mechanic. The process generally involves supporting the transmission with a jack, unbolting the mount from the crossmember and transmission, and swapping in the new part. You will need a good socket set, a jack, and jack stands.
How many transmission mounts does my Buick Century have?
Your 1956-1972 Buick Century has one transmission mount, located at the rear of the transmission, and two engine mounts at the front of the engine.
Technical Specifications
OEM Part Numbers: Varies significantly by year, model, and transmission type.
Available materials include OEM-style rubber and aftermarket performance polyurethane. The Lakewood aftermarket option is made of polyurethane and often features a safety-interlock design.
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.