Gearbox Overhaul Explained: What You're Actually Paying For
What happens inside a proper automatic gearbox overhaul, from teardown to warranty, and how to tell a real rebuild from a wash-and-respray.
Two workshops can both write "overhaul" on an invoice and mean completely different things. One means a full engineering rebuild measured against factory tolerances. The other means the box got washed, resealed, and sent back out with a prayer. The price difference between them might only be a thousand ringgit. The difference in what you receive is enormous, and this guide is about telling them apart before you pay.
Anatomy of a real overhaul
The teardown, and the question that matters
The gearbox comes out and comes completely apart. Every clutch drum opened, every bearing off the shaft. And here the builder is looking for something specific: not just what burnt, but why it burnt.
A cooked clutch pack almost always has an upstream cause. A worn valve-body bore bleeding pressure. A cracked sealing ring. A half-blocked cooler. Replace the clutches without finding that cause and the fresh clutches meet the same fate, usually about a year later. When someone brings us a gearbox that was "overhauled" elsewhere twelve months ago, this missed step is usually the story.
Measurement
Bores, end-float, clearances, all checked against the factory manual with actual instruments. The hard parts (planetary gears, drums, shafts, pump) get measured, not glanced at. This is the tedious, invisible step that separates engineering from cleaning.
Parts that must be new
- Every friction plate and every steel plate, not just the burnt ones
- The complete soft-part kit: seals, O-rings, gaskets, sealing rings
- Bushings and thrust washers
- Filter, and the band where the design uses one
- The torque converter, rebuilt or replaced. Bolting a debris-filled converter onto a fresh gearbox is the classic comeback failure, and it still happens every day
- Updated components for the model's documented weaknesses: better friction material, revised valve-body parts, improved pistons where the aftermarket has solved a factory problem
The valve body and the electronics
Valve body rebuilt or exchanged, solenoids tested against spec rather than just checked for a click, and on mechatronic units the control module bench-tested. The cooler circuit gets flushed or replaced too, because old debris sitting in the cooler is the other classic way a rebuild dies young.
Assembly and proof
Clean assembly with measured clutch clearances, correct fluid, adaptation relearn, then a proper road test through every gear, cold and hot. If the workshop can't describe their road-test routine, they don't have one.
What the market charges
| Gearbox type | Typical overhaul cost |
|---|---|
| Perodua / Proton 4AT | RM 2,500 – 3,500 |
| Japanese 4–6AT (Toyota, Honda, Mazda) | RM 3,500 – 5,500 |
| CVT (Honda, Nissan, Proton) | RM 4,000 – 7,500 |
| DSG / DCT (VW, Proton 7DCT, Ford) | RM 5,000 – 9,000 |
| Continental AT (ZF, Mercedes 7G/9G) | RM 7,000 – 12,000+ |
These move around with parts pricing and with what the teardown uncovers. An honest shop quotes a range before teardown and a firm number after. Be suspicious of anyone who does it the other way around.
Signs you're being sold the cosmetic version
- A confident, oddly low price before anyone has opened your gearbox
- No teardown report, no photos of your actual unit on the bench
- The whole job done in a day
- Your old torque converter going straight back in
- A warranty that's verbal, vague, or missing a mileage figure
- A parts list that reads "gasket set" and nothing else
One question that does most of the filtering
Ask this before you hand over the keys: "What's the warranty, in writing, in months and kilometres?"
A builder who trusts his own work says six to twelve months without blinking. A builder who plans to blame your driving style when it fails will start explaining why warranties don't really work for gearboxes. Both answers tell you exactly what you need to know.
For the record: MNA Dynamic Torque in Shah Alam and IM Dynamic Torque in Simpang Ampat both answer that question in writing before the gearbox comes out, with teardown photos of your actual unit along the way. Ask them anything on WhatsApp — including the awkward questions from this guide.
Common questions
- 01How long does a gearbox overhaul take in Malaysia?
- Three to five working days is normal: a day for removal and teardown, a day or two waiting on parts and machining, a day for assembly, then road testing before release. Continental units with mechatronic work can stretch to a week.
- 02Is an overhauled gearbox as good as new?
- A proper overhaul replaces every wear component: friction plates, steels, seals, bushings, bands, filter. A good builder also fits updated parts that fix the design's known weak points, which means the rebuilt unit can actually outlast the original. Where it matters, yes, it's effectively new at a third to half the cost.
- 03Should I overhaul my gearbox or buy a used or recond unit?
- Overhaul your own unit, almost every time. You know its history, every wear part is new, and it comes with a warranty. A used unit is somebody else's mileage in a freshly painted casing. Used only makes sense when your casing or hard parts are destroyed.