TCU tuning · DCT and automatic gearboxes
Gearbox tuning, explained.
An engine tune changes how much torque your car makes. But your gearbox has its own computer - the TCU - and it's still running the factory calibration, written for a stock engine. A gearbox tune recalibrates the TCU so the transmission works with your tune, not against it.
Why it matters on a tuned car
Tuned engine, factory gearbox calibration
Hyundai and Kia calibrated the gearbox for factory torque. Tune the engine and the TCU keeps running the same shift, clamping and torque tables - which is why a tuned car can feel slurry on the first hard pulls, or change up before you want it to.
- The 7-speed DCT's factory clamping has no margin over the torque the engine reports
- Clutch adaptation can take a few hard pulls to catch up with extra torque
- The 8-speed DCT forces an upshift at around 7,000 rpm - even in manual mode
- The gearbox can ask the engine to hold torque back
Gearbox tunes for US customers are done remotely - US$450. Contact us for the details of how it works for your car.
Contact usGearboxes we tune
What we change, gearbox by gearbox
All of our gearbox tunes are fully released. You don't need an engine tune first. Not sure which gearbox your car has? Get in touch and we'll tell you.
- More clamping force - on the dyno, our Stage 2 tune held 389 Nm at the flywheel in a Kia Cerato GT (the Forte GT in the US) with no clutch slip
- Sharper, faster shifts under power
- Creep removal
- No auto-shifting in manual mode
- Faster, more aggressive shifts
- Separate shift points for auto and manual, including higher auto-mode shift points
- Holds gears to the engine's rev limiter - we've had one bouncing off it at 7,400 rpm
- More torque capacity
- Creep reduction or removal
Got Bluelink? Cars with Bluelink use a newer TCU that can't be tuned. TCUs aren't VIN-locked, so we can tune a spare TCU for your car instead.
- More aggressive shifts
- More clamping force
- Revised rev limits
The same kind of improvements as our DCT tunes.
- More clamping force
- Faster shifts
- Kick-down delete
- Manual mode with no forced upshifts
Proven on a customer car
More torque. No slip.
The same Kia Cerato GT (sold in the US as the Forte GT) with a 7-speed DCT, before and after our Stage 2 gearbox tune. It now makes more torque - and the clutch holds it from the very first full-throttle pull.
June 2025 - before our Stage 2 gearbox tune
322 Nm
peak torque at the flywheel
43%
clutch slip on the first full-throttle pull
Sept 2026 - with our Stage 2 gearbox tune
389 Nm
peak torque at the flywheel
None
clutch slip on the first full-throttle pull
June 2025 - before our Stage 2 gearbox tune Sept 2026 - with our Stage 2 gearbox tune
Slip is worked out from logged engine speed against road speed: how far the engine runs ahead of the gear it's in. Lines are lightly smoothed; the take-off and the shift are illustrative, as our logs start after take-off. Readings inside about ±5% are logging resolution, not slip. Torque figures are flywheel numbers from the same dyno (Dyno Dynamics, shootout mode).
See the numbers
| Full-throttle pull | June 2025 | Sept 2026 |
|---|---|---|
| 1st | 43% slip | none measurable (max 3%) |
| 2nd | 5% (within noise) | none measurable (max 3%) |
| 3rd | 4% (within noise) | - |
| Peak torque (flywheel) | 322 Nm | 389 Nm |
Creep removal
Less creep, longer gearbox life
Creep keeps a DCT's clutch slipping every time you're stopped off the brake or crawling in traffic. That's heat and wear the gearbox doesn't need - especially in a dry-clutch DCT, and in 8-speed DCTs running upgraded clutches.
- Creep removal on the 7-speed dry-clutch DCT - proven on customer cars
- Creep reduction or removal on the 8-speed DCT
- Less clutch heat and wear every time you're sitting in traffic
Creep removal or reduction is part of your remote gearbox tune - just ask for it when you order.
Contact usWhat the TCU decides
What the gearbox computer controls
Every shift, every take-off and every bit of clutch clamping is decided by the TCU, from tables set at the factory. A gearbox tune recalibrates those tables.
The TCU picks every shift from tables of road speed against pedal position, with a different set for each drive mode. It also forces an upshift as you near the rev limit - on the 8-speed DCT, even in manual mode.
A dual-clutch shift is one clutch letting go while the other takes up the drive. How quickly that handover happens is calibrated separately for shifts under power and shifts off the throttle - so shifts can be sharper when you're on it and still smooth when you're cruising.
The TCU works out how hard to clamp each clutch from the torque the engine reports. When the engine makes more than the calibration expects, there's less margin - and the clutch can slip until the gearbox's adaptation learns the difference.
Lift off the brake and a DCT slips its clutch so the car creeps forward like a traditional auto. That creep is a calibrated torque and target speed in the TCU - not something fixed in the hardware.
How quickly the clutch takes up drive when you pull away, and the engine speed it holds for a brake-held launch, are both set in the TCU.
The gearbox and engine computers talk constantly. During a shift - and as an overall ceiling - the TCU can ask the engine to cut torque. The gearbox has a real say in how much of your engine tune you actually get.
Pricing
What it costs
Before you book
Good to know
How much is a gearbox tune?
US$450, done remotely. Contact us and we'll walk you through how it works for your car.
Do I need an engine tune first?
No - a gearbox tune doesn't need an engine tune.
How is it done?
Gearbox tunes for US customers are done remotely. Contact us for the details of how it works for your car.
My 8-speed DCT car has Bluelink. Can it be tuned?
Not its own TCU - cars with Bluelink use a newer TCU that can't be tuned. But TCUs aren't VIN-locked, so we can tune a spare TCU for your car instead. Get in touch and we'll talk you through it.
Does a gearbox tune remove the torque limits?
No - we don't delete the factory torque limits. We raise how much torque the gearbox will let the engine make, and give the gearbox more capacity to handle it.
Can I flash a gearbox tune at home?
Contact us for the details of how your remote gearbox tune is delivered. Our own tuning tool will also add TCU flashing - see the Cherry Tuning Suite.
Are the 8-speed DCT and automatic tunes still in beta?
No. All of our gearbox tunes are fully released.
Ready to tune your gearbox?
Buy a remote gearbox tune, or contact us for the details of how it works for your car.