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The usual advice for picking a workshop is a list of questions to ask. With transmissions it works better the other way round. Listen to what the workshop asks you. A real gearbox specialist will not quote over the telephone from a one-line description, because the same symptom can mean a cheap sensor or a full rebuild. The quality of the questions coming back down the line is the earliest and most honest evidence you will get.
Question One: Which Gearbox Is It, Exactly?
Expect to be asked for the make, model, year and engine, and often the chassis number. Behind that question is the fact that the word automatic covers three unlike machines. A conventional unit uses a torque converter and planetary gears. A continuously variable transmission uses a belt or chain between two pulleys. A dual-clutch gearbox is closer to two automated manuals sharing a casing. Each has its own weak points, fluid, tools and software. A workshop that does not ask is preparing to guess.
Question Two: What Does It Do, and When?
Next should come questions about behaviour. Does it slip, bang, judder or delay? In which gears? Cold, hot, or only after a long queue? Under light throttle or hard acceleration? Any warning lamp, and has the car locked itself in one gear? Is there a noise, and does it follow engine speed or road speed? The person asking is narrowing the fault to hydraulic, electronic or mechanical causes before seeing the car.
Question Three: What Has Already Been Tried?
A careful workshop also wants the history. When was the fluid last changed, and with what? Has anyone already replaced a part, cleared codes or added an additive? Has the car been towed, flooded or driven with the warning on? Previous work matters because the wrong fluid or a part-finished repair changes what is likely to be found. Concealing an earlier attempt does not lower the price. It only lengthens the diagnosis that you will be paying for.
The Road Test They Insist On
After the questions comes an invitation to bring the car in, and an insistence on driving it. An independent transmission repair workshop worth using will road-test with a scan tool connected, watching commanded and actual gear ratios, fluid temperature and pressures while reproducing your complaint. A firm that offers a rebuild price without this step is selling a product, not solving your problem.
A Look in the Pan Before Naming a Price
The next piece of evidence is physical. With the car raised, the technician checks for leaks, examines the fluid’s colour and smell, and on many units removes the pan or a drain plug to inspect what has settled. Fine grey sludge on the magnet is ordinary. Friction material, brass or steel flakes mean internal wear. You should be shown this, or sent a photograph. A recommendation to overhaul that rests on a look in the pan is far more credible than one resting on a code alone.
Reading the Workshop Itself
While you are there, look around. Transmission work demands cleanliness, so a dedicated, tidy strip-down bench is a good sign and a gearbox open on a gritty floor is not. Ask whether units are rebuilt on the premises or sent elsewhere, and who carries the warranty if they are sent out. Ask whether the workshop can program and adapt control units for your make, because many modern gearboxes will not shift properly after repair until that electronic step has been done.
The Quotation: Ranges, Not Promises
Before stripdown, nobody can know everything that is worn, so be wary of a single confident figure. A sound quotation gives a base price for removal, dismantling, a standard kit of clutches, seals and gaskets, refitting and fluid, then lists likely extras with individual prices: torque converter, valve body, solenoids, bearings or a pump. It should promise a call with photographs once the unit is apart, and state what you would owe if you chose to stop at that point.
Parts on the Table
Ask what goes in. Friction plates and seal kits vary in quality, and reputable builders name the brands they use. Steel plates may be reused if flat and unburnt. A valve body may be new, remanufactured or repaired in-house, each at a different price and risk. The torque converter should be cut open and rebuilt or replaced, not merely flushed, when debris has circulated. The fluid must be the exact specification for the gearbox, because near-equivalents can spoil shift quality.
The Guarantee, Written Down
The guarantee tells you how much confidence the workshop has in its own work. Get the period and the mileage limit in writing, along with what is covered: parts and labour, or parts only. Ask what voids it, such as overheating, towing a trailer or work by others. Ask whether the cooler and its lines are flushed or replaced as standard, since contamination left there is a leading cause of repeat failure.
Narrowing to One Name
Set your notes on two or three workshops side by side. Favour the one that asked the most precise questions, drove the car, showed you the evidence and gave a structured quotation with a written guarantee. Price should separate only those that pass these tests, and the cheapest figure is often the one with the most left out. If the car is close to the end of its certificate, ask the gearbox specialist whether repair is sensible at all. An honest answer to that question is the final test.
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