You have probably seen this R&T article but I have a quattro question >>
 

This article states that the front wheels are driven by default, then the rears pull in during slippage. I have searched the web several times looking for a good explaination of how the quattro works but can never find much. Anyone have a good explaination or an article that explains the quattro operation?<ul><li><a href="http://www.roadandtrack.com/article.asp?section_id=31&amp;article_id=1014&amp; page_number=1&amp;preview=">http://www.roadandtrack.com/article.asp?section_id=31&amp;article_id=1014&amp; page_number=1&amp;preview=</a</li></ul>

From the source
 

<ul><li><a href="http://www.haldex-traction.com/default.htm">http://www.haldex-traction.com/default.htm</a</li></ul>

The TT is based on a Haldex >>>>
 

four wheel drive system. The "true" quattro is based on a torsen, full time four wheel drive. If you look at it on paper, the TT is actually a better solution. It's lighter, more efficient, and overall performs the same function. All of the A4's, 6's and 8's have the torsen version and are constently battling weight problems.......

Downside...the TT "quattro", requires maintenance every 20k, while the truw "quattro", is sealed and requires no maintenance......

Re: You have probably seen this R&T article but I have a quattro question >>
 

Use the search feature on this site. Type in Quattro AWD to find out what you would like to know.

Ironically, the new Haldex system...>>
 

according to an "inside connection" (volvo application):

The S60R has our second generation of the 4WD system. It doesn't need any
replacement of the oil (slightly different disc material and
different type of oil).
There's not even a drain on the new Volvo system!

quattro hasn't always been a Torsen diff, it has evolved and will continue.

Hmmm, time to go to the Volvo parts department ;)

Thanks guys, always an education

huh....so what was it originally, cause according to this>>>
 

it's been around for 20yrs.....<ul><li><a href="http://www.audi.com/jsp/crossfeatures/lexicon/lexiconDetails.jsp?lexiconId=17948&amp;lexiconChar =Q&amp;domainId=1&amp;languageId=4">http://www.audi.com/jsp/crossfeatures/lexicon/lexiconDetails.jsp?lexiconId=17948&amp;lexiconChar =Q&am

That is a cool animation, haven't seen that before...
 

The ur quattro originally had a manually locking center diff, they didn't start using a Torsen diff until 1988.<ul><li><a href="http://www.quat.com/urqhome.html">http://www.quat.com/urqhome.html</a</li></ul>