Transmission Mounts: What Do They Do?

Have you ever noticed that sometimes the smallest item can have an enormous impact on the overall functionality of a complex design? For example, take transmission mounts. They are small, unassuming little widgets that aren’t very impressive looking. But they are literally the glue that holds your vehicle’s transmission together. Okay, not literal glue, but still, they do a bang-up job. When transmission mounts fail, your vehicle may experience shaking or a clanging noise due to a worn or broken bracket and bushing. Keep reading for more details.

What Are Transmission Mounts?

There are several types of engine and drivetrain mounts used on most passenger vehicles, SUVs, and trucks. Engine or motor mounts hold the engine in place. Transmission mounts support the transmission end of the drivetrain. Manufacturers typically equip cars with at least one transmission mount (and sometimes two or more) to help keep the transmission securely attached to the frame.

How Do They Work?

Transmission mounts typically consist of two parts: the bracket and bushing. The bracket secures the transmission to the chassis, while the bushing reduces drivetrain shaking and noise in the vehicle’s interior cabin.

What Is The Bracket and Bushing Made Of?

Manufacturers typically use steel to make the transmission mount bracket, and either urethane or rubber for the bushing. The factory then bolts, welds, or chemically bonds the bracket and bushing together. On many vehicles, the bracket and bushing are inseparable and must be replaced as a single unit.

Why Do They Fail?

Typically, transmission mounts last around ten years, or 60,000-100,000 miles. They wear out over time due to rubber oxidation and metal fatigue from transmission shaking. Other contributing factors of failure can include: 

• Aggressive driving
• Extreme temperatures
• Front-end auto collisions
• Improper engine and/or transmission lifting, removal, or repairs
• Leaking automotive fluids

Symptoms Of Failing Transmission Mounts

Unusual shaking and clanging noises from your vehicle can be nerve-racking. If these symptoms get worse while accelerating, you may have bad transmission mounts. It’s important to schedule a diagnostic inspection with your auto technician if you suspect your vehicle has failing transmission mounts to prevent more damage. Let’s look at the particulars.

Banging & Clanging Noises

Failing transmission mounts often produce banging and clanging noises during acceleration or while braking. A loose or worn bracket and bushing no longer secures the transmission properly, resulting in excessive transmission or drivetrain movement. These loose parts bump into other components or even the chassis, creating unusual clanging noises.

Rocking & Shaking

A very common symptom of bad transmission mounts is increased vehicle rocking & shaking. It’s usually most noticeable when your vehicle is in gear, idling at a stop sign or traffic signal, with your foot on the brake. The vibrations often get worse during acceleration from a complete stop. You may feel shaking in the steering wheel, gear shifter, or through your seat. Unlike tire-related vibrations, which are felt most when your vehicle is moving at speed, transmission mount shaking is most pronounced when your vehicle is in gear but not moving.

Sagging Transmission or Engine

You may visibly see your vehicle’s transmission sag or move (under your hood) if your transmission mounts are severely worn or broken. Visible sagging is most common in front-wheel-drive cars, where the transmission is partly visible in the engine compartment. A securely mounted transmission will remain stationary while changing gears, with only minor movement. Excessive rocking or sagging indicates that one or more transmission mounts have failed.

Shifty Shifting

Most vehicles with automatic transmissions change gears without any driver input. However, failing transmission mounts can result in a shifty shifting experience. An improperly supported transmission can move or shake during gear changes. This movement may create an abrupt or jerky gear change. You may also experience a hesitation before the transmission shifts from park to drive or vice versa. Failing transmission mounts may affect gear alignment, making shifts feel rougher even though the transmission is (technically) functioning correctly.

Transmission Repairs in Midland, MI

All A’s Automotive & Transmission Repair is a family-owned and operated business in Midland, MI. Our thoroughness and experience have earned us an excellent reputation for transmission repairs. Our technicians will inspect your vehicle’s transmission mounts to determine if a failing bracket and bushing are causing the shaking and clanging noise. 

Make An Appointment

To schedule your next appointment, please call us at (989) 631-4672 or visit our website and fill out our convenient online appointment form.