Gearbox Mount Bushes

Nolathane gearbox mount bushes replace the worn rubber bushes that locate a gearbox to the crossmember or chassis. On many vehicles the gearbox isn?t held by a single rubber block. Instead, it?s located by bushes in a crossmember bracket or by a steady rod with a bush at each end. Those bushes control how much the gearbox can rock, twist and shift every time you accelerate, brake or change gear.

When gearbox mount bushes wear, the whole engine and gearbox assembly moves more than it should. The result is clunks, vibration, a vague gear change and extra stress on the driveline. Polyurethane gearbox mount bushes hold the gearbox firmly for a more positive shift and smoother, more direct power delivery.

How Gearbox Mount Bushes Work

The engine and gearbox are bolted together and supported as one unit. Under acceleration, the torque from the engine tries to rotate the whole assembly in the opposite direction to the crankshaft. Under braking or engine braking, it tries to rotate the other way. Gearbox mount bushes resist that rocking motion while absorbing vibration from the gearbox.

Depending on the vehicle, gearbox mount bushes may be found:

• In a bracket where the gearbox bolts to the crossmember
• At each end of a gearbox steady rod or torque rod that links the gearbox to the body
• In a mount that locates the front or side of a gearbox on some all-wheel-drive and transverse layouts

Each position plays a part in keeping the gearbox located, and each wears over time, so inspect them all together.

Why Gearbox Mount Bushes Wear

• Repeated torque reversals every time the throttle is applied and released
• Heat from the gearbox, exhaust and engine
• Oil and transmission fluid leaks softening rubber
• Age and ozone cracking and hardening rubber
• Performance driving, launch control and higher engine output
• Towing and heavy loads on 4WDs and pick-ups

Because these bushes are often hidden above a crossmember or behind heat shields, they?re easy to overlook during routine servicing and are often the last bushes to be checked.

Signs of Worn Gearbox Mount Bushes

• A clunk or thump when taking off, changing gear or lifting off the throttle
• The gear lever moving or vibrating on its own under acceleration
• A vague, sloppy or notchy manual gear change
• Increased vibration through the floor and gear lever at idle
• Driveline vibration that changes with throttle load
• The engine visibly rocking when revved with the vehicle stationary
• Cracked, split or perished rubber at the gearbox mount or steady rod

Gearbox Mount Bushes and Shift Feel

On manual vehicles, the gear lever is connected to the gearbox through a linkage or selector mechanism. If the gearbox is free to move on soft or worn mounts, every gear change has to overcome that movement before the selector engages. That?s why worn gearbox mounts often feel like a sloppy or rubbery shift.

Firmer gearbox mount bushes keep the gearbox steady, so the linkage moves the selector directly. Combined with fresh shifter bushes, they can transform the feel of a tired manual gearbox, making each shift shorter, crisper and more precise.

Polyurethane vs Rubber Gearbox Mount Bushes

Factory gearbox mount bushes are soft rubber, chosen to isolate as much engine and gearbox vibration as possible. That softness lets the gearbox move, and as the rubber ages and is exposed to oil and heat, it gets softer still.

Polyurethane gearbox mount bushes hold their shape and keep the gearbox located under load. Nolathane has been making polyurethane suspension bushings since 1974, originally developed to replace brass bushes in hillclimb competition. The signature red polyurethane is made in a range of durometers (hardness grades) for each position, and offers outstanding abrasion resistance, high load-bearing capability, increased tensile strength and resistance to oil, grease, ozone and weathering.

The honest trade-off is that firmer gearbox mount bushes transmit more engine and gearbox vibration into the cabin than soft factory rubber, especially at idle and low engine speeds. Most enthusiasts accept this in return for a sharper shift and less driveline clunk, but drivers who prioritise cabin refinement should weigh it up.

Who Gearbox Mount Bushes Suit

• Performance and all-wheel-drive vehicles where launch, cornering and gear change precision matter
• Manual vehicles with a sloppy shift caused by gearbox movement
• 4WDs and pick-ups that tow or carry heavy loads
• Classic vehicles whose original rubber gearbox mounts have deteriorated
• High-kilometre vehicles with clunks and vibration from tired factory mounts

Fitting Gearbox Mount Bushes

Fitting suits professional workshops and experienced home mechanics. As a general guide:

1. Support the vehicle securely on stands.
2. Support the gearbox with a transmission jack or suitable support.
3. Remove the crossmember, mount bracket or steady rod as required.
4. Remove the old bushes, which may need a press, and clean the housings.
5. Fit the new bushes with a grease suitable for polyurethane where specified.
6. Refit the bracket or rod, raise the gearbox into position and tighten all fasteners to specification.
7. Check gear lever movement and driveline angles, then road test.

Replacing gearbox mount bushes at the same time as engine mounts, shifter bushes or a clutch replacement saves labour, as much of the same access is needed.

Choosing the Right Gearbox Mount Bushes

Gearbox mount designs vary between vehicles, gearboxes and drivetrains, and some vehicles use different bushes in different positions. Confirm the vehicle, engine, gearbox type, drivetrain and model year before ordering. Each listing shows the position and vehicles the kit suits, and our fitment guarantee means the kit you order for your vehicle is confirmed to suit it.

Shop Gearbox Mount Bushes

Driveline shunt and vague shifts are both covered by Nolathane's transmission parts range.

Find the gearbox mount bushes for your vehicle, then order online with fast shipping or have them fitted by a Nolathane reseller. 60-day returns give you time if a part isn?t right, and our local support team can help whether you?re curing a driveline clunk, sharpening a manual gear change or restoring a classic.