Reader Question: AWD Coupling?

0
3098
Print Friendly, PDF & Email

Here’s the latest reader question, along with my reply!

Josh asks: Do FWD based AWD have a center differential or a viscous coupling system, because I thought that only RWD based AWDs have a center differential or viscous coupling. Can you please send me a diagram, as well as an explanation, because I am confused on how these AWDs work.

My reply: As in a truck-type 4WD system, all AWD systems – whether based on a transverse engine/FWD layout or longitudinal/RWD layout – have an additional component to transfer power to the other pair of driven wheels (the rear wheels in a FWD-based layout or the front wheels in a RWD-based layout). It can be mechanical or viscous-type coupling, which uses silicon to engage plates in response to different wheel rotation speeds, causing power transfer to equalize rotation speed and thus control wheel slip. In some cases, the two systems are combined, to reduce lag time in between slippage and reaction of the system.

A more detailed technical explanation can be found here.

The confusion arises because there are differences between the various manufacturer’s AWD systems whereas truck-type 4WD is fundamentally the same across the board (e.g., a two-speed mechanical transfer case that can be engaged for gear reduction and front and rear differentials, etc.)

I’ve embedded a graphic from Subaru highlighting some of the FWD/RWD/AWD vs.4WD differences.

. . . .

Got a question about cars, Libertarian politics – or anything else? Click on the “ask Eric” link and send ’em in!

If you like what you’ve found here please consider supporting EPautos. 

We depend on you to keep the wheels turning! 

Our donate button is here.

 If you prefer not to use PayPal, our mailing address is:

EPautos
721 Hummingbird Lane SE
Copper Hill, VA 24079

PS: Get an EPautos magnet or sticker or coaster in return for a $20 or more one-time donation or a $10 or more monthly recurring donation. (Please be sure to tell us you want a magnet or sticker or coaster – and also, provide an address, so we know where to mail the thing!)

My eBook about car buying (new and used) is also available for your favorite price – free! Click here.  If that fails, email me at EPeters952@yahoo.com and I will send you a copy directly!

 

Share Button

LEAVE A REPLY

Please enter your comment!
Please enter your name here