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<blockquote data-quote="Razzmatazz" data-source="post: 17460" data-attributes="member: 1603">That's a tough one.&nbsp; I have a 2007 LS AWD with 105k miles (90% highway).&nbsp; Fortunately I haven't had that problem yet.&nbsp; But please be aware that computer can do weird things and give misleading messages when it gets bad data from the sensors or isn't running well.&nbsp; Pretty much anytime there's a Check Engine Light (even a P0405 EGR valve code), the computer turns off the unrelated AWD, traction-control and Stabiitrak and says on the display that they need to be serviced.&nbsp; (It's ridiculous-- especially if a CEL appears during a snowstorm when you need AWD/traction-control.)&nbsp; My original EGR valve lasted 13 years before I got a P0405.&nbsp; I replaced the EGR valve and the CEL disappeared and the AWD/Stabilitrak/Traction-control started working again.&nbsp; (What?!?&nbsp; Replacing the EGR-valve fixed the transmission?!?)&nbsp;&nbsp; About one year after I replaced the EGR valve, I got another P0405 followed by a P1779-- &quot;Engine Torque Delivered to Transmission Control Module&quot;.)&nbsp; At that point, it bucked when I drove down the highway-- seemingly a transmission issue, not an engine issue since the engine was purring along when it bucked.&nbsp; I found it hard to believe that the EGR valve failed after 1 year.&nbsp; And it was due for a 100k spark-plug change, so I changed the spark-plugs, cleared the codes, and the problem disappeared.&nbsp; No more bucking and no more CEL.&nbsp; And I didn't need to replace the EGR valve.&nbsp; (What?!? Changing the spark plugs fixed the EGR valve and the transmission?!?!?)&nbsp; The spark plugs were not fouled but they were much more worn than I would have expected.&nbsp; (I think I'll change them at 75k next time.)&nbsp; I assume that the worn spark-plugs were causing some kind of bad combustion which was confusing the computer, causing a P0405, and causing the computer to send strange signals to the transmission.&nbsp; Who knows?&nbsp; My point is that your transmission problem MAY not be a transmission problem.If it hasn't been done on schedule, consider replacing the spark plugs (due every 100k, but maybe better to do at 75k) and consider flushing the transmission fluid (due every 100k).&nbsp; Replacing the EGR valve is really easy and cheap, so you may want to start there to see if the problem goes away.&nbsp; (Don't buy the Delphi EGR valve on Amazon that supposedly fits.&nbsp; It doesn't fit.)&nbsp; Check the EGR-valve tube too while you're in there.&nbsp; Are you sure that your transmission fluid is full?&nbsp; How many miles does it have?&nbsp; FWD or AWD?</blockquote>

[QUOTE="Razzmatazz, post: 17460, member: 1603"] That's a tough one. I have a 2007 LS AWD with 105k miles (90% highway). Fortunately I haven't had that problem yet. But please be aware that computer can do weird things and give misleading messages when it gets bad data from the sensors or isn't running well. Pretty much anytime there's a Check Engine Light (even a P0405 EGR valve code), the computer turns off the [B]unrelated [/B]AWD, traction-control and Stabiitrak and says on the display that they need to be serviced. (It's ridiculous-- especially if a CEL appears during a snowstorm when you need AWD/traction-control.) My original EGR valve lasted 13 years before I got a P0405. I replaced the EGR valve and the CEL disappeared and the AWD/Stabilitrak/Traction-control started working again. (What?!? Replacing the EGR-valve fixed the transmission?!?) About one year after I replaced the EGR valve, I got another P0405 followed by a P1779-- "Engine Torque Delivered to Transmission Control Module".) At that point, it bucked when I drove down the highway-- seemingly a transmission issue, not an engine issue since the engine was purring along when it bucked. I found it hard to believe that the EGR valve failed after 1 year. And it was due for a 100k spark-plug change, so I changed the spark-plugs, cleared the codes, and the problem disappeared. No more bucking and no more CEL. And I didn't need to replace the EGR valve. (What?!? Changing the spark plugs fixed the EGR valve and the transmission?!?!?) The spark plugs were not fouled but they were much more worn than I would have expected. (I think I'll change them at 75k next time.) I assume that the worn spark-plugs were causing some kind of bad combustion which was confusing the computer, causing a P0405, and causing the computer to send strange signals to the transmission. Who knows? My point is that your transmission problem MAY not be a transmission problem. If it hasn't been done on schedule, consider replacing the spark plugs (due every 100k, but maybe better to do at 75k) and consider flushing the transmission fluid (due every 100k). Replacing the EGR valve is really easy and cheap, so you may want to start there to see if the problem goes away. (Don't buy the Delphi EGR valve on Amazon that supposedly fits. It doesn't fit.) Check the EGR-valve tube too while you're in there. Are you sure that your transmission fluid is full? How many miles does it have? FWD or AWD? [/QUOTE]

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