The engine knocked for a week, then quit on the way home. Or the transmission started slipping, and now the car revs and goes nowhere. Either way you’re facing the same choice, and it comes down to two numbers: what the repair costs, and what the car is worth once it’s fixed. We won’t guess at either one here, because both swing widely by make, mileage and shop. What we can do is show you how to get real numbers and what to do with them.
Get the real numbers first
Start with a written estimate. The FTC’s auto repair guide says it should name the condition being repaired, the parts needed and the expected labor charge, and you should get a signed copy. It should also say the shop will contact you before going past a set amount of time or money.
Three more tips from the same guide matter here. Ask whether there’s a diagnostic charge if you take the work elsewhere, since many shops bill for diagnostic time. Get a second opinion on expensive or complicated repairs. And consider a shop that only diagnoses and doesn’t sell repairs, because it has no stake in the answer.
Then get the other number: what the car would sell for running, in its real condition, rust and mileage included. Not what you paid, and not what it would be worth with a new engine and new tires.
Illinois law runs the same comparison in specific cases. Section 3-117.1(b) of the Vehicle Code treats a repossessed car, a fleet vehicle or a flood car as salvage when repairs, labor included, would cost more than 50% of its fair market value without the damage. Those are legal definitions, not advice for your driveway. But the logic is the one you’re applying.
Signs the engine or transmission is finished
Rule out the cheap causes before you write the car off. The FTC points out that a “bad starter” may be a dead battery or a poor connection, and that poor transmission performance can come from a disconnected hose or a plugged filter rather than a failed part, so the technician should check the simple items first.
These are the symptoms that usually lead to talk of replacement rather than repair:
- A heavy, rhythmic knock. The FTC links this to worn crankshaft or connecting rod bearings.
- Overheating with steam and a hot metallic smell. The FTC says to pull over at once, because continued driving can cause severe engine damage. If the car was driven on after that, the damage may already be done.
- Oil and coolant mixing, or a visible hole or crack in the engine block.
- A transmission with no response going from neutral into drive or reverse, or one that slips so the engine speeds up and the car doesn’t follow, after fluid, hoses and filter have been checked.
Only a technician can confirm the cause. Use that diagnosis, plus the estimate, in the table below.
Repair or sell: the decision table
| What you find out | Leans toward | Why |
|---|---|---|
| The fault is a hose, filter, battery or connection | Repair | A small fix on a car that’s otherwise fine |
| The estimate is small next to the car’s running value, and the body and frame are solid | Repair | You get back a car worth more than you spent |
| The estimate comes close to the running value, or passes it | Sell | You’d pay more than the fixed car would be worth |
| The engine or transmission needs replacing, and the car also has rust, frame damage or other failing systems | Sell | The next big repair is already lined up |
| You plan to keep the car for years and know its history | Price the repair | A known car with a fresh drivetrain can make sense |
| The car is also wrecked, flooded or burned | Sell | The drivetrain is no longer the main problem |
If the table points to selling, call (708) 838-5553 and describe what failed. A dead engine or transmission doesn’t stop us from making an offer.
Replacement engine and transmission options
When the answer is replacement, the FTC sorts parts into three groups:
- New: generally built to the original manufacturer’s specifications, by the carmaker or an independent company.
- Remanufactured, rebuilt or reconditioned: the FTC says these terms generally mean the same thing, parts restored to sound working condition. Many manufacturers warranty the part but not the labor to install it.
- Salvage (used): taken from another vehicle without alteration. Sometimes it’s the only source, though the FTC warns that its reliability is rarely assured.
Labor is a big part of an engine or transmission swap whatever the part, so make sure it’s itemized on the estimate. Then ask the hard question: if the replacement fails, who pays to pull it out again?
Why a car with a dead drivetrain is still worth something
A blown engine doesn’t touch the doors, glass, wheels, seats or the metal in the body and frame. Illinois even licenses a business type for exactly this. An automotive parts recycler acquires used vehicles mainly to sell their parts, or to dispose of them as scrap.
The failed part isn’t always the whole story either. A car with a blown engine may have a good transmission, and the reverse happens too. The Illinois scrap processor law, 5-401.3, bars scrap processors from reselling vehicles or essential parts as such, except engines, transmissions and powertrains, so those parts can have a second life. What a particular car brings depends on its make, size and condition; our guide on why junk car offers differ explains the factors. Pickups and vans with dead drivetrains are covered on the trucks, vans and SUVs page, and the makes we buy list covers the rest.
Don’t drive it to the buyer
Nursing a knocking engine or a slipping transmission a few more miles can turn a damaged part into a destroyed one. You don’t have to. Our free junk car towing means the car leaves on our own tow truck, whether it died at the curb in Chicago Lawn or sits in a driveway in Burbank. It’s one of the cars that don’t run we buy as they sit. Same-day pickup is often possible, and you’re paid at pickup by Cash App, Zelle or cash.
Next step
Once you have the estimate, get a cash offer and compare the two side by side, or call (708) 838-5553. Offers don’t expire, so there’s no rush while you wait on a second opinion. More guides for sellers are on our tips page.
Sources
- Auto Repair Basics (Federal Trade Commission, Consumer Advice)
- 625 ILCS 5/3-117.1, When junking certificates or salvage certificates must be obtained (Illinois General Assembly)
- 625 ILCS 5/5-401.3, Scrap processors required to keep records (Illinois General Assembly)
- 625 ILCS 5/1-105.3, Automotive parts recycler (Illinois General Assembly)
Treat this page as general information rather than legal advice. Rules change; check the official page or call the office named before you act on them.
Will you buy a car whose transmission is gone but the engine still runs?
Yes. A car that starts but won't move, or slips so badly it can't be driven safely, counts as a non-running car for us. Don't drive it over, since that can finish off parts that still work. We tow it free from the street, driveway or garage, and you're paid at pickup by cash, Zelle or Cash App.
Should I pay for a diagnosis before deciding?
Usually, if the car would otherwise be worth keeping. The FTC notes that many shops charge for diagnostic time, so ask about that fee before you agree, and get the findings and the estimate in writing. If the car was already near the end of its life, a diagnosis may not change the answer, and you can sell it as it sits.
Is a rebuilt engine better than a used one?
They're different products. The FTC groups remanufactured, rebuilt and reconditioned parts together as parts restored to sound working condition, and notes many come with a warranty on the part but not the labor. A salvage, or used, engine comes out of another vehicle unaltered, and you rarely get any assurance about how long it will last. Ask the shop what each option's warranty covers.