Over 40 Years of Expertise
Hamilton's Transmission Specialists
When it comes to gearboxes, clutches, differentials, and torque converters, Marshall Transmissions is in a league of its own. As part of the wider Marshall Transmissions & Automotive family, our transmission division brings decades of hands-on specialist experience that most general workshops simply can't match.
Whether you're dealing with a slipping automatic, a noisy gearbox, or a complete transmission failure, you're in the right place.
What We Do
Transmission work is highly specialised — it's not something every mechanic is trained or equipped to handle. At Marshall Transmissions, it's all we've done for over 40 years. Our team rebuilds, repairs, and reconditions transmissions in-house, which means faster turnarounds, better quality control, and more cost-effective outcomes for you.
We specialise in:
- Manual gearbox repair and rebuild
- Automatic transmission repair and overhaul
- Clutch repair and replacement
- Differential diagnosis and repair
- Torque converter rebuild and replacement
- Transmission fluid services
- Fault diagnosis and driveline assessment
We work on all makes and models — Japanese, European, American, and everything in between.
Signs You May Have a Transmission Problem
- Transmission issues rarely fix themselves, and catching them early almost always saves money. Look out for:
- Slipping gears — the engine revs but the car doesn't accelerate properly
- Shuddering or jerking — particularly when changing gears or pulling away
- Difficulty shifting — grinding, hesitation, or resistance when changing gears
- Unusual noises — whining, clunking, or humming that changes with speed
- Burning smell — often a sign of overheating transmission fluid
- Warning lights — transmission or check engine lights on your dash
- Fluid leaks — reddish fluid pooling under your vehicle
If you're experiencing any of these, don't wait. The longer a transmission issue is left, the more expensive the repair typically becomes.
Transmission Types We Work On
Automatic Transmissions
Automatic transmission problems can be some of the most complex and costly repairs in a vehicle. Common issues include slipping between gears, delayed engagement, overheating, and complete failure. Our team has extensive experience rebuilding and overhauling automatic transmissions across a wide range of vehicles — and we'll always tell you honestly whether a rebuild, a reconditioned unit, or a replacement is the most sensible option for your situation.
Manual Gearboxes
Manual gearboxes are generally more straightforward, but a worn or damaged gearbox still needs expert attention. We repair and rebuild manual gearboxes, replace synchros, bearings, and seals, and source hard-to-find components for older or imported vehicles.
CVT (Continuously Variable Transmissions)
CVTs have become increasingly common in modern vehicles — particularly Japanese brands like Toyota, Honda, Nissan, and Subaru — and they require a very different approach to diagnosis and repair than conventional automatic or manual gearboxes. Rather than fixed gear ratios, a CVT uses a belt and pulley system to deliver seamless acceleration, which means the failure modes and repair techniques are unique.
Common CVT symptoms include shuddering at low speeds, a whining or humming noise under load, hesitation when accelerating, or the vehicle going into limp mode. If you're experiencing any of these, it's important to get it looked at quickly — CVT repairs become significantly more expensive when left too long. Our team has experience diagnosing and servicing CVT units, and we'll give you an honest assessment of whether a service, repair, or replacement is the right path forward.
Classic Car & Hot Rod Transmissions
Older and modified vehicles present a unique set of challenges, parts can be hard to source, tolerances differ from modern vehicles, and not every workshop has the patience or knowledge to do the job properly. We do.
Whether you're restoring a classic to original spec or building a hot rod with a custom drivetrain setup, our team enjoys the challenge of working on vehicles that fall outside the everyday. We can rebuild vintage gearboxes, source hard-to-find components, advise on performance transmission upgrades, and work alongside you to get the result you're after. Give us a call to discuss your project, every build is different and we're happy to talk through the options.
Electric & Hybrid Vehicle Transmissions
While fully electric vehicles don't use a traditional multi-speed transmission, they do have reduction gearboxes, single-speed drive units, and complex drivetrain components that require specialist knowledge to work on safely. Hybrid vehicles often combine a conventional automatic or CVT with an electric motor, creating an even more complex system.
This is an evolving area and not all transmission workshops are equipped to work on EV and hybrid drivetrains. Our team is committed to staying current with the technology, and we're able to carry out transmission-related diagnostics and repairs on a range of hybrid vehicles. If you're unsure whether we can help with your specific vehicle, give us a call on 07 847 2799.
Torque Converter Specialists
The torque converter is one of the most overlooked components in an automatic transmission — and one of the most critical. Problems with a torque converter often get misdiagnosed as broader transmission issues, leading to unnecessary and expensive repairs.
At Marshall Transmissions, we rebuild torque converters in-house. It's a specialist capability that sets us apart from the vast majority of workshops in New Zealand, and it means we can offer a more accurate diagnosis, a faster repair, and a better result for your vehicle.
Differential Repairs & Rebuilds
The differential is one of those components most drivers never think about — until it starts causing problems. It's a critical part of your drivetrain, allowing your wheels to rotate at different speeds when cornering, and when it wears or fails the effects can range from annoying to dangerous.
Differential work is specialist territory. The tolerances are tight, the components are precise, and a poorly repaired differential can cause serious damage to the rest of your drivetrain. Our team has the experience and equipment to diagnose, repair, and rebuild differentials properly, on front-wheel, rear-wheel, and all-wheel drive vehicles.
Signs your differential may need attention:
- Whining, humming, or clunking noises — particularly on corners or under acceleration
- Vibration that changes with speed
- Handling that feels unpredictable or loose
- Fluid leaks underneath the rear or front of the vehicle
- Tyre wear that seems uneven or abnormal
Differential services we carry out:
- Differential fluid changes and servicing
- Bearing and seal replacement
- Ring and pinion gear replacement
- Full differential rebuilds
- Limited slip differential (LSD) servicing and repair
- Transfer case inspection and repair
As with all our work, we'll diagnose accurately before recommending anything, and give you a clear quote before any work begins. If you're hearing noises you can't explain or your vehicle isn't handling the way it should, give us a call — it's worth getting it checked sooner rather than later.
Your authorised repairer
We Work With Your Insurer or Lender
Getting your car repaired shouldn't be a financial headache. Marshall Transmissions & Automotive is an authorised repairer for a range of insurance providers and finance options, including:
- WINZ (Work & Income)
- Autosure
- Provident Insurance
- Protecta / Assurant Insurance
- Janssen
- Quest Insurance
- MTF Finance
Not sure if we work with your provider? Give us a call, we're happy to help you figure it out.
FIND OUT MORE
Frequently Asked Questions
How do I know if my transmission is failing?
The most common signs are slipping gears - where the engine revs but the car doesn't accelerate properly - shuddering or jerking when changing gears, difficulty shifting, unusual whining or clunking noises, a burning smell, warning lights on the dash, or reddish fluid leaking underneath your vehicle. If you notice any of these, get it assessed as soon as possible. Transmission problems rarely improve on their own and the cost of repair generally increases the longer it's left.
How much does a gearbox repair cost?
Transmission repair costs vary significantly depending on the type of transmission, the make and model of the vehicle, and the extent of the damage. A minor service or fluid change is very different in cost to a full rebuild. We always carry out a proper diagnosis before quoting, and you'll receive a clear, written quote before any work begins. There are no surprises. Call us on 0800 22 8000 and we can give you a better idea once we know what you're dealing with.
How long does a transmission repair take?
It depends on the scope of work. A transmission fluid service can often be completed the same day. A full rebuild typically takes several days, as components need to be stripped, inspected, sourced if required, and reassembled correctly. We'll give you a realistic timeframe when we quote the job and keep you updated throughout.
Do you repair both automatic and manual transmissions?
Yes. We work on automatic transmissions, manual gearboxes, CVT transmissions, DSG transmissions, and differentials across all makes and models. If you're unsure whether we can help with your specific vehicle, give us a call and we'll confirm before you bring it in.
What is a torque converter and how do I know if mine is faulty?
The torque converter sits between the engine and the automatic transmission and transfers power from one to the other. When it fails, the symptoms can be easy to confuse with broader transmission problems - which is why accurate diagnosis matters. Common signs of a faulty torque converter include shuddering at certain speeds, slipping, overheating, and unusual noises. Marshall Transmissions is one of the few workshops in New Zealand that rebuilds torque converters in-house, which means a more accurate diagnosis and a better result.
Can I still drive my car if I suspect a transmission problem?
In most cases we'd recommend against it. Continuing to drive with a transmission fault can turn a manageable repair into a much more expensive one - and in some situations it can be unsafe. If your vehicle is slipping, jerking, making unusual noises, or showing a warning light, call us and we'll advise based on what you're describing. If you're not confident driving it in, let us know and we can talk through your options.
Do you offer a warranty on transmission repairs?
Yes. Our repairs are backed by a warranty on workmanship. The specific terms depend on the nature of the repair, so ask our team for details when you book your vehicle in.
What brands and makes do you work on?
All of them. We work on Japanese, European, American, and other imported vehicles across the full range of makes and models - Toyota, Nissan, Honda, Subaru, Mazda, Ford, Holden, BMW, Mercedes, Audi, Volkswagen, and more. If you have a less common or classic vehicle, give us a call and we'll let you know what we can do.