Transmission Parts for MG MGB

Nolathane transmission parts focus on the mounts and bushes that hold the MG MGB gearbox in place. A transmission mount supports the weight of the gearbox, resists the twisting force it creates under power, and isolates its vibration from the body. When transmission mounts wear, the gearbox starts to move under load, causing clunks, vibration through the cabin and a vague, imprecise gear change.

Polyurethane transmission mount bushes restore firm gearbox location for smoother power delivery and a more positive shift. They suit passenger cars, performance and all-wheel-drive vehicles, 4WDs, utes and classic cars.

What a Transmission Mount Does on the MG MGB

The engine and gearbox are bolted together and supported as one unit, usually on two or three engine mounts and at least one transmission mount. The transmission mount, also called a gearbox mount, typically sits under the rear of the gearbox on a crossmember, or at the side of the gearbox on front-wheel-drive and transverse layouts.

The mount has three jobs:

• Support the weight of the gearbox
• Resist the torque reaction that tries to twist the engine and gearbox when power is applied
• Absorb vibration so it isn?t transmitted into the cabin

Some vehicles also use a gearbox steady rod or torque rod, a link with bushes at each end, to stop the gearbox rocking back and forth under acceleration and braking.

Types of Transmission Mounts

Transmission mounts come in several designs:

• Rubber mounts are the most common factory type, quiet and compliant but prone to cracking and sagging with age
• Hydraulic mounts contain fluid to dampen vibration further, and can leak and collapse when worn
• Bush-type mounts and steady rods use cylindrical bushes in a bracket or link to locate the gearbox
• Polyurethane mounts and bushes hold the gearbox more firmly and resist oil, heat and age
• Solid mounts give the most direct connection but transmit the most vibration and are mainly suited to competition use

Each listing shows the position and vehicles the part suits.

Signs of a Worn MG MGB Transmission Mount

• A clunk or thud when taking off, shifting into drive or reverse, or lifting off the throttle
• Excess vibration through the floor, seats or gear lever, especially at idle
• The gear lever moving on its own under acceleration or braking
• Vague, notchy or imprecise gear changes on manual vehicles
• Driveline vibration at certain speeds
• Visible cracks, splits or separation in the mount rubber, or leaking fluid from a hydraulic mount
• The gearbox sitting lower than it should, or visibly rocking when the engine is revved

Worn engine mounts can cause similar symptoms, so it?s worth checking all of the engine and gearbox mounts together before deciding which parts to replace.

Why Worn Transmission Mounts Matter

A gearbox that moves too much doesn?t just make noise. It changes the angle of the tailshaft (driveshaft or propshaft) or drive shafts every time power is applied, which can cause driveline vibration and extra wear on universal joints, CV joints and the centre bearing. On manual vehicles, a moving gearbox pulls the shift linkage with it, making gear changes less precise. Replacing worn mounts protects the surrounding drivetrain as well as improving refinement.

Polyurethane Transmission Mount Bushes

Factory rubber mounts and bushes are soft so they isolate vibration, but they compress, crack and soften with heat and oil exposure. Polyurethane transmission mount bushes hold the gearbox more firmly and keep their shape far longer.

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, which matters in a hot, oily position next to the gearbox.

The honest trade-off is that firmer transmission mounts transmit more engine and gearbox vibration into the cabin than soft rubber, particularly at idle. On most vehicles the change is modest, and many drivers prefer the sharper shift and reduced driveline clunk. For vehicles where cabin refinement matters most, consider that trade-off before upgrading.

Transmission Mount Replacement Cost

Transmission mount replacement cost is driven mostly by labour and access. On many rear-wheel-drive vehicles, the mount sits under the gearbox and can be replaced by supporting the gearbox and removing the crossmember bolts. On some front-wheel-drive and all-wheel-drive vehicles, access is tighter and other components may need to be removed. Replacing all worn engine and transmission mounts in one visit, or combining the job with a clutch or gearbox service, avoids paying for the same access twice.

Fitting Transmission Mounts on Your MG MGB

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, taking care not to damage the sump or gearbox pan.
3. Remove the crossmember or mount bracket bolts and lower the gearbox slightly if needed.
4. Remove the old mount or bushes and clean the mounting surfaces.
5. Fit the new mount or bushes with a grease suitable for polyurethane where specified.
6. Raise the gearbox back into position and tighten all fasteners to the vehicle manufacturer?s specification.
7. Check driveline angles and gear lever movement, then road test.

Replace any mount bolts that are stretched or designed for single use.

Choosing the Right Transmission Parts for Your MG MGB

Transmission mount designs vary widely between vehicles, drivetrains and gearbox types. Confirm the vehicle, engine, gearbox, drivetrain and model year before ordering. Our fitment guarantee means the part you order for your MG MGB is confirmed to suit it.

Lifetime Warranty

Nolathane transmission mount bushes are backed by a lifetime warranty against manufacturing defects in material and workmanship, for the original vehicle they?re fitted to.

Shop Transmission Parts for Your MG MGB

Find the transmission parts for your MG MGB, 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 drivetrain clunk, sharpening a manual gear change or restoring a classic.