Over the past few weeks we’ve looked at a to help load vehicles onto trailers, to help ensure lug nuts and bolts are properly torqued, and a for removing plastic rivets with ease. This week’s cool tool is a fluid transfer pump that makes fluid changes easier in some vehicles and may be necessary in others.

This suggestion was recommended by a number of readers, my mechanic and Opposite-lock. These people use fluid transfer pumps for everything from oil changes to filling transfer cases with fluid.

A lot of cars make fluid changes easier by having fluid drain plugs on their engine oil and transmission pans or differential housings. For these vehicles, getting fluids out is as simple as opening the plug and letting the fluid drain into an appropriate container. Then, you crack open the fill port and fill it back up (remember to open the fill port before you open the drain port!).

But some vehicles don’t have drain plugs while others have fill ports that are hard to access.

Take the first-generation Volkswagen Touareg as an example. Volkswagen filled the SUV’s transmission with a “lifetime” fill of fluid. There’s no transmission dipstick, and topping off the thing is harder than it should be. No fluid is ever really a lifetime fluid, and it’s still a good idea to check your fluids to make sure they’re present in the right volume and clean.

For the Touareg, this means that you have to get under the vehicle and crack open the fill port located on the bottom of the transmission on the pan.

If fluid drips out, it’s full. If fluid doesn’t, it should be topped up. Ah, but how are you supposed to fill this thing without covering your face in transmission fluid?

This is where a fluid transfer pump comes in. These work by creating a vacuum that sucks fluid out of one location and deposits it into another. In this case, it can be used to suck fluid out of a container and put it into the Volkswagen’s transmission.

Some obscure or weird cars don’t have an oil drain plug. A transfer pump becomes necessary for these sorts of vehicles because there often isn’t any other good way to get the old oil out of the engine.

Check out this video by that shows how even the cheapest fluid transfer pump makes fluid changes so much easier.

This is another tool I’m picking up for myself so I can change the transmission fluid in my Touareg.

These things can be found for as low as $20 just about anywhere you get tools. The one featured in that review above is on for about $18.

But one thing to note is that the super cheap ones may not work with fluids like gasoline with ethanol. Also, pumping thick fluids like axle oil can require some real strength, and you’ll find that sometimes the hoses on these transfer pumps blow off.

Do you know of a weird or unique but must-have tool that every wrencher should have? Do you want to see us put a type of tool to the test and see how it performs? Shoot me an email or drop it down in the comments!