Is Using A Transmission Fluid Additive Worth It?

Every auto parts store in America has a wall of engine and transmission additives that, no matter what's actually in them, promises to fix or rebuild some component or system that needs actual, mechanical work. There's some kind of tincture for almost every problem, from leaking radiators to worn valve seals to slipping transmissions, and just about all of them are auto parts store products to steer clear of. Think about it, if you could really, truly fix your car with a $10 bottle of goop from your local AutoZone, how would professional mechanics stay in business?

That said, while most of them are snake oil, some of them actually do something. Some engine oil additives can slow or temporarily stop oil leaks by softening old, hardened gaskets and seals, for example, and fuel injector cleaners can actually work wonders for your vehicle. Nevertheless, other additives often do more harm than good, both to your wallet and your engine.

What about transmission additives, though? Do the various "clutches in a bottle" additives do anything for an old or worn out transmission? Is adding a transmission additive to your transmission fluid worth it? Well, let's talk about it.

Is it worth adding a transmission additive? Well, as it is with a lot of automotive questions, it depends on your car's situation. Additives that have friction enhancers in them or claim to stop automatic transmissions from slipping have their place, but there's a catch. You should only really use something like this if you're trying to squeeze a few more shifts out of an already failing transmission. Say, like, you're trying to get a vehicle with a bum gearbox to the shop for a transmission rebuild. It should be noted that these additives only really work, when they work at all, in automatic transmissions. If you have a manual that's slipping or grinding, no amount of magic parts store elixirs is going to fix that.

If your transmission is fine, or is just acting a little weird, and you're worried about keeping it working correctly, you don't need a transmission additive. Regular maintenance — changing your trans fluid, filter, and pan gasket according to the manufacturer's recommended maintenance intervals — will make sure your properly functioning transmission stays that way. As I'm sure you've heard me state before, an ounce of prevention (maintenance) is worth more than a pound of cure (costly transmission repairs).