How 4WD Works - Four Wheel Drive

How does four wheel drive work? This video explains the workings of four wheel drive (4WD), and gives a definition in order to differentiate different types of four wheel drive and all wheel drive. Four wheel drive simply means 4 wheels are driven, and many times this is accomplished through the use of a transfer case.

Note: I have a poor vocabulary, and may end up calling the transfer case a transaxle. Please ignore it when I say "transaxle" and replace with "transfer case." Thanks!

Here are the links I mentioned.

Ackerman Steering:

Differentials Explained:

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[EngineeringExplained]

I love how so many people have to clarify they already know the material. Either way, it doesn't matter haha. I didn't know all this up until a couple months ago, there's no shame in not knowing! Learning is important, so hopefully something good can come from it. But thanks for watching and participating in discussion!

Wind up simply refers to the torque that passes thru your drivetrain due to the wheels not being able to rotate at various speeds. The outside tire is hindered from rotating.

[Brancovtn]

You can say that again... Thanks for taking the time and effort to help us understand car concepts a lot better. I've been looking for this kind of info for a lonnng time, and it's a blessing to find a YouTube channel that is fully dedicated to just that. As well as adding in recommendations so newbies such as myself don't make any careless mistakes in the future. Keep it up!

[AndyR]

Hey pal, been working on cars my entire life. And sadly, I'm an engineer . But besides shortcutting and not ripping it apart to figure it out, I've never known how a 4WD works. Now that my transmission went out, I needed to get an idea. I needed to know what does what. You helped immensely. Thanks!

[RamosDominicano]

Great video Jason! I have watched well over 100 of your videos, but I have to admit, this is probably the one that I learned the most on. Keep up the good work bud!

[EngineeringExplained]

Yeah I suppose. You seem to be enjoying this channel, glad you like it! Cheers.

[EngineeringExplained]

It's an even lower gear set for when higher torque is needed and speed isn't necessary. (The vehicle is stuck, etc..).

[EngineeringExplained]

Very good to hear, glad you've learned!

[kronkodile]

I've only watched about 3 minutes of this video and already have a HUGE understanding of this, thanks a lot!

[alansaer]

Thanks for the video man, thus gave me a better understanding of 4X4

[EngineeringExplained]

Subarus use AWD, yes, and it's always active. The setup on Subarus is also symmetrical so the weight is balanced.

[EngineeringExplained]

So a center diff isn't needed because in this scenario the transfer case splits the power between the front and the back, and the front/rear diffs make up for the differing speeds of the wheels.

[stalinyourleader]

Once on a drive with my father, he ripped out the driveshaft of his truck (as it was snapped in half) and we kept on driving in 4 wheel drive with just the front wheels.

[wannabeangler]

I thoroughly enjoy all your videos! You must be a genius in order to know so much about the working variations in vehicles. I'm not a mechanic nor am I any kind of grease monkey, but have become highly interested in mechanics in my later years. I toy with ideas on my truck and explore different ways to better the output performance. When I can't find an answer, I come to your videos. I'm obviously more inclined to the working knowledge of my truck, but my mental capacities are limited. Thanks again!

[EngineeringExplained]

Lock-up usually refers to the brakes locking the tires up, preventing them from rotating. This happens in cars without ABS, such as formula 1 cars, where the drivers are expected to feel the exact forces the car can withstand without sliding.

[toyotaoforlando]

Great video! It sure makes it easy for non-car folks to understand 4WD. 

[icychap]

Great video - thanks for sharing this!

[maxasok]

Thank you for the great Video explanation. Theoretical explanation with the aid of diagrams help me to better understand the topic. Thank you and I'm looking forward to learn more. Cheers...

[EngineeringExplained]

A third differential is not totally necessary. I'm assuming these vehicles can switch out of this mode, and perhaps use just the rear tires? If so 4WD would be reserved for situations like being on dirt, when the tires could slip easily and not cause additional wear.

[wilXwyane]

One days good enough for me!

Thanks again!

[EngineeringExplained]

Perhaps you could. Check with forums and see what other people have done. But the cheaper option might be to swap cars. I don't know, I just recommend braking it down by cost, unless you just want to do it for fun, in which case, go for it! Unique things like that are awesome in my opinion, just not too cost effective.