The automatic gearbox jerks when it changes gear
A jerk on the change is a shift that is taking too long or arriving too hard, and on a modern automatic that is as often an electronic or hydraulic pressure problem as a mechanical one. That distinction is worth understanding before anybody quotes you, because the two ends of it are very far apart in cost: degraded fluid, a solenoid, a pressure sensor or software that has adapted badly around a fault are all at the cheap end, and a worn clutch pack or torque converter is at the other. The fault codes and live pressure data are read first for exactly that reason — nobody should be opening a gearbox to find out what a scan tool can say in ten minutes.
Can I keep driving it?
Drivable, but do not leave it
Do not treat this as something to live with. Automatic gearboxes tend to damage themselves once shifts stop happening cleanly — slipping generates heat, heat degrades the fluid further, and the fluid is what carries the pressure that makes the shift. The gap between a fluid-and-solenoid job and a rebuild is often just how long it was driven. If it is also slipping, banging into drive, or there is a dark patch under the middle of the car, stop driving it and have it collected.
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
- It bangs into gear when I put it in drive
- The revs go up but the car does not go faster
- 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 battery goes flat if I leave the car for a few days Fine daily, flat after a weekend, is either a battery that no longer holds charge or a parasitic drain — and a new battery only fixes one of them. Both are measured in Sharjah.
- The temperature gauge climbs in traffic Normal on the move and climbing at a standstill means the car cannot shed heat without airflow — fans, radiator, thermostat, water pump or a leak. What to do if it reaches the red.
- It clicks when I turn the key but will not start One loud clunk points at the starter; rapid clicking points at current — battery, connection or charging. They feel identical, and the wrong guess buys a starter that does not fix it.
- White smoke comes out of the exhaust Thin vapour on a cold start is normal. White smoke that continues warm, hangs in the air and smells faintly sweet is coolant — and the car will still drive perfectly while it happens.