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Discussion Starter · #1 ·
It seems that there is a lot of mis-information and understanding about how the angle gear and AWD system work. So I am starting this thread to help people understand what it is all about. <p>There is a crude diagram someone drew before which I will try to find so people can understand graphically. Also, I am not an expert on every in and out of the system so others can chime in.<p>The engine and transmission are transversely mounted. This means that in order for the power, which makes it's way through the end of the crankshaft into the gearbox and out the front halfshafts all in a manner perpendicular to the fore-aft axis of the car, must turn 90 degrees in order to turn the rear driveshaft. <p>This is where the angle gear comes in. It is a set of beveled gears which allow the direction of the power to spin the rear driveshaft. <p>The collar gear / spline sleeve attaches a transmission output shaft to the angle gear. <p>Now, the transmission output shaft, angle gear and rear driveshaft are all locked together mechanically. This means no matter what, these items are always turning. <p>When the driveshaft gets to the rear of the car, it enters the Haldex Coupling, sometimes called the AOD (Active on demand) coupling. It is a controllable coupling which engages and dis-engages according to the requests of the computers. <p>The Haldex is connected to the rear differential to which power is sent as the Haldex engages. <p>The DEM or Differential Electronic Module is a computer which sits on the Haldex and is part of the control system. There is a pressure / temperature sensor on it which goes bad. This has been one of the most frequent causes of a loss of AWD. <p>Another frequent cause is when the software in the DEM gets confused (running on an AWD dyno for instance) and freaks out an needs to be reset. <p>Another cause is for the spline sleeve to crap out. <p>The angle gear "failing" itself is rather unheard of. There have been cases where the angle gear has needed replacement due to the spline sleeve being fused to it, or by debris from the dead spline sleeve munching on the angle gear internals. <p>The angle gear has been prone to leaking or weeping from two locations. The first is the vent, which has been upgraded. It is possible to install a new vent. <p>The second is from the casing mating surface. This can be re-sealed. <p>
 

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Want me to get some pics of everything listed ? <p>Tranny <br>Sleave <br>Angle gear <br>Drive shaft <br>
 

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Re: (Chilled Man)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>Chilled Man</b> »</i></TD></TR><TR><TD CLASS="quote">Want me to get some pics of everything listed ? <p>Tranny <br>Sleave <br>Angle gear <br>Drive shaft <br></TD></TR></TABLE><p>That would be great since I am still new to the R and trying to understand the mechanics of this angle gear mess!
 

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Re: Angle gear and AWD: How it works. (Needsdecaf)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>Needsdecaf</b> »</i></TD></TR><TR><TD CLASS="quote"><p>The angle gear "failing" itself is rather unheard of.<p></TD></TR></TABLE><p>Mine just failed in my XC90 at 110K miles-- and my dealer says I'm not the first.<p>As for symptoms, I never experienced an oil leak. For more than a year prior to failure it gave a high pitched whine. That was it.
 

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Re: Angle gear and AWD: How it works. (Needsdecaf)

Excellent piece of work! Thanks for highlighting the REAL failure point!<p>Too many times when something like angle gear failure is mentioned, it conjures up the illusion of shucked gear teeth. I know of none of those, however it does sound like one XC-90 owner had improper teeth alignment, and or failed bearings.
 

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How can one tell if they have the new 'case-hardened' angle gear or the regular one? I have a 2006 S60R with geartronic, so I'm assuming I'm safe? Would be nice to know if there are differences in looks etc.! Thanks.
 

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Discussion Starter · #9 ·
Re: Angle gear and AWD: How it works. (paxcam)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>paxcam</b> »</i></TD></TR><TR><TD CLASS="quote"><p>Mine just failed in my XC90 at 110K miles-- and my dealer says I'm not the first.<p>As for symptoms, I never experienced an oil leak. For more than a year prior to failure it gave a high pitched whine. That was it. </TD></TR></TABLE><p>Did your angle gear fail? Or did your spline shaft fail. <p>This is an important difference.
 

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Re: (Jexx)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>Jexx</b> »</i></TD></TR><TR><TD CLASS="quote">How can one tell if they have the new 'case-hardened' angle gear or the regular one? I have a 2006 S60R with geartronic, so I'm assuming I'm safe? Would be nice to know if there are differences in looks etc.! Thanks.</TD></TR></TABLE><p>The angle gear was not case hardened. The collar gear was. <p>
 

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Actually in the 98-00 cars the angle gears kick the bucket all the time its the Spline sleaves that dont since most end up with offset tires and there not enough HP in most cars to rip apart the spline sleave
 

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Re: (Chilled Man)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD><i>Quote, originally posted by <b>Chilled Man</b> »</i></TD></TR><TR><TD CLASS="quote">Actually in the 98-00 cars the angle gears kick the bucket all the time its the Spline sleaves that dont since most end up with offset tires and there not enough HP in most cars to rip apart the spline sleave</TD></TR></TABLE><p>Hell, my S70 must be a beast then <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/biggrin.gif" BORDER="0">. My sleeve was shot @ 124k miles (took the angle gear with it if you recall) <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/mad.gif" BORDER="0">... <p>Joe
 
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