The revs rise but the car does not speed up
This is slipping, and it is the one automatic gearbox symptom worth treating as urgent on its own. Engine speed and road speed are supposed to be locked to each other by whichever clutch pack is holding for that gear; when the revs climb and the car does not, something that should be gripping is letting go. The set to be separated is a hydraulic pressure problem, degraded or low fluid, a failing torque converter, or worn friction material — and they are not equally expensive. What matters more than which one it is today is that slipping is self-worsening in a way most faults are not: the slip itself generates heat, heat cooks the fluid, and cooked fluid can no longer hold the pressure that stops the slipping.
Can I keep driving it?
Do not keep driving it
Stop driving it. This is not caution for its own sake — the gap between a fluid and pressure repair and a full rebuild on the same gearbox is very often just how many more kilometres it covered while slipping, and every one of those kilometres is doing the damage that decides which bill you get. If it has to be moved it should be collected rather than driven, and many automatics should not be flat-towed at all.
How we find out which one it is
Gearbox diagnosis, rebuild, replacement — and the three prices next to each other.
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01
We rule out everything that is not the gearbox
An engine misfire, a collapsed mount, a worn driveshaft joint or a wiring fault can all feel exactly like a gearbox from the driving seat. Those are cheap to find and cheap to fix, and they get checked before the word rebuild is used. This is also where the formal term ناقل الحركة belongs, on a diagnosis sheet rather than in a conversation.
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02
The box is judged from outside first
Slip is measured, not felt: the input and output shaft speeds are compared against the ratio the box should be holding. Line pressure is read on a gauge. The fluid is looked at and smelled. Those readings tell us whether the box is worn, whether a solenoid or valve body is at fault, or whether it is something outside the box entirely.
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03
Three options, three prices, side by side
Rebuilding your own box, fitting a used unit and fitting a new one differ in price, in how long the car is off the road, and in what is known about the part. You get all three written down together, including what we do not know about a used unit, so you are choosing rather than being steered.
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04
Once the box is open, nothing is decided without you
On a rebuild the clutch packs come out onto the bench and the drums, bushes and valve body are gone through. If the strip reveals damage the estimate did not cover — a scored drum, a burnt pack, debris that has been through the pump — the job stops exactly there. You are told what was found, what it adds and what the alternative now costs, and the box goes no further until you answer.
Other things this system does
- The gear jerks when it changes
- It bangs into gear when I put it in drive
- It does not move at all when I select drive
- It will not change up until the engine is screaming
- There is a whine that changes with speed
- It shudders at a steady speed on the motorway
- A red or dark fluid patch under the middle of the car
Other complaints with a page
- The steering wheel shakes when I brake A shake felt only under braking points at the front brakes, not the tyres. What separates disc wear from heat distortion from a bearing, and how it is checked in Sharjah.
- The car pulls to one side when I brake Pulling only under braking is a difference between the two front brakes — caliper, hose, pad or slide pin. Pulling all the time is usually alignment. How the two are told apart.
- There is a knocking noise over speed bumps A knock over a bump is free play in the suspension or steering. Drop links, bushes, top mounts and shocks all sound identical from the seat — how they are separated on a lift.
- The AC is cold when moving but warm in traffic Cooling at speed but not at a standstill points at heat rejection at the front — fans, a blocked condenser, or the wrong charge — not at the refrigerant circuit. Checked in Sharjah.