You notice your transmission is acting just a little different; one of the shifts feels a little sloppier or is taking longer to complete. It’s not really bad — you hope! — but you want to avoid a rebuild.

So you head over to your local parts store, and there it is: an entire aisle of additives and chemicals, promising everything from better gas mileage to a new transmission in a can. And all for under $10! Could it possibly be true?

Not a chance.

What you’re seeing is an extension of the old “snake oil” remedies: The ones that promised to cure you of everything from bad breath to gout, and everything in between. What was in it? You really didn’t want to know. And the odds of it working weren’t particularly good.

Today we have laws preventing anyone from selling quack medicines. But there’s nothing preventing anyone from doing the same thing with auto additives. So every auto store has an entire aisle dedicated mostly to quack cures for your automotive ills. Of course, not everything in those bottles is a complete lie. So how do you know which are legit? Look at the promises: If it claims to rebuild your transmission with a single can, avoid it. No one could do that… if they could, it would instantly put every transmission shop out of business.

But if they promise things that are at least reasonable — improving the transmission’s resistance to high temperatures or providing additional lubrication — there’s at least a chance it’s legitimate.

You can also check online: See what other folks have to say about the product. If you start seeing a lot of reviews that suggest you avoid it, take them to heart.

And, if you’ve noticed a difference in the way your transmission is behaving, bring your car to your nearby Cottman center. The technicians there are experts in transmission technology: They’ll check your transmission’s operation and let you know if something’s wrong.

The good news here is that more than half the cars that come in with transmission trouble don’t end up needing their transmissions rebuilt. The repair is a lot less involved… and a lot cheaper. So before you drop a dime on snake oil for your transmission, bring your car to your nearby Cottman center. They’ll help get your transmission working like new again, at a fair and honest price.