What TCU tuning changes
The transmission control unit decides when to shift, how firmly, how quickly it will drop a gear when you ask, and how long it holds a ratio. Manufacturers set those conservatively for smoothness and for the worst case they can imagine.
Tuning it can sharpen shift speed, reduce the hesitation before a kickdown, adjust shift points so they suit the torque curve the engine actually has, and raise clamping pressure where the standard setting is marginal.
Why it matters after an engine remap
If you add torque to an engine and leave the gearbox software alone, the box is now making decisions based on an engine that no longer exists. At best the shift points are in the wrong place. At worst the clutches are being asked to hold more than the standard clamping pressure was set for.
That is the main reason we raise it. On a mapped automatic, matching the transmission to the engine is usually the difference between a car that is quick and a car that is pleasant.
Which gearboxes
Dual clutch and modern torque converter automatics are the usual candidates, and what is possible varies a lot by manufacturer and by unit. Some are very open, some are effectively closed.
Tell us the vehicle and we will tell you honestly whether there is anything worth doing, including when the answer is no.
Gearbox Tuning questions, answered
What is TCU remapping?
Remapping the transmission control unit, the software that decides when and how your automatic gearbox shifts, as opposed to the engine ECU.
What does gearbox tuning actually change?
Typically shift speed, shift points, kickdown response, how long a gear is held, and clamping pressure where the standard setting is marginal for the torque being produced.
Do I need it if I have had an engine remap?
On an automatic it is usually worth considering. Adding torque without adjusting the transmission leaves the gearbox making decisions based on the old engine, and can ask more of the clutches than the standard settings allow for.
Will it make the car less comfortable?
It does not have to. How firm the shifts feel is one of the things being set, so it is adjusted to what you want rather than to a fixed setting.
Is it safe for the gearbox?
When done properly it is generally kinder, because the box is matched to the engine it actually has. Done badly it is not, which is why it is written per vehicle rather than loaded generically.
Does it work on manual gearboxes?
No. A manual has no transmission control unit to map. The engine remap is the whole job there.
Which gearboxes can you tune?
Many modern dual clutch and torque converter automatics, though it varies a lot by manufacturer and unit. Tell us the vehicle and we will tell you what is possible.
Can it be reversed?
Yes. The original transmission file is saved before anything is written.
Will it affect my warranty?
It can, in the same way an engine remap can. If the vehicle is under warranty, leased or on finance, say so at the enquiry stage.
Do I need to tell my insurer?
Yes, it is a modification and should be declared.
How long does it take?
Usually comparable to an engine remap, around one to three hours depending on the vehicle and how the TCU is accessed.
Can you do engine and gearbox together?
Yes, and on an automatic that is normally the sensible way to do it so the two are written to work together.
Want a straight answer about your vehicle?
Tell us what it is and how you use it, and we will tell you honestly what is worth doing.
Call 07773 694570What people say
★★★★★ 5.0 from 18 Google reviewsHighly recommend!! I recently had my VW Caddy remapped with Mercia Remaps. I'd converted the back into a camper and put a Tentbox on the roof, the added weight had really affected the performance and fuel consumption. Mark from Mercia was an absolute legend during the whole process.
Harvey Broadbent · Google review
Had my car remapped by Mark, great friendly service. Took the time to explain to me what he was doing & gave me options on which kind of remap I’d like. Car feels so much quicker & feels a lot more responsive. Highly recommend.
Reece Bennett · Google review
Top guy, sorted some issues out on my Jag, it also drives so much better and faster than ever. Would definitely recommend
jeff Slade · Google review
Get a price for gearbox tuning in your area
Tell us the vehicle and how you use it and we will come back with a straight answer, including when a map is not worth doing.
Quickest way is to ring:
- We come to you across your area and the surrounding villages
- Usually about an hour to ninety minutes on site
- The original file is kept, so it can always go back to standard
Gearbox Tuning across the Midlands
We are mobile, so we cover a wide area from the workshop in Lutterworth. These are the towns with a dedicated page, and we cover the villages around each of them too.
- Gearbox Tuning in Rugby
- Gearbox Tuning in Coventry
- Gearbox Tuning in Leicester
- Gearbox Tuning in Lutterworth
- Gearbox Tuning in Northampton
- Gearbox Tuning in Kettering
- Gearbox Tuning in Hinckley
- Gearbox Tuning in Nuneaton
- Gearbox Tuning in Leamington Spa
- Gearbox Tuning in Warwick
- Gearbox Tuning in Corby
- Gearbox Tuning in Loughborough