35R Transmissioin Wave Plate

Schumi78

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Hello,

So last Friday my wife was driving to work and said that the car was shifting hard in certain gears very sporadically and was revving high when going through certain gears as well. No CEL came on. She made it to work and we assumed it might have been a hiccup, she'd drive it home at the end of the day and we'll take it down to the local GM dealer on Saturday am to look into it.

When leaving work, she called saying the CEL was now on and the car wouldn't go into reverse. So I left work to go check out, preparing to call a tow truck and take it to the local GM dealer in our town. While on the way there, she called me saying that she let the car warm up, the CEL went off and it went into reverse. I told her to stay put because I didn't want her driving home and getting stranded on the side of the road during rush hour.

When I got there, there we no weird noises coming from anywhere, CEL was not on and fwd/rev gears were working. Drove around the parking lot a bit to check it out and both the manually and automatic seemed to be working fine. So I decided to drive home while she followed me just in case I ran into issues. Everything was going fine until about half way home when the car was shifting hard in/out of 3rd gear (couple times heard some loud bangs). Stopped at a red light then found the car was stuck in 1st gear. It would not manually shift nor would the #1s appear on the dash when put into manual..

Pulled over into a parking lot, called a tow truck and had it dropped at the dealer. Service manager called me the next day and said that it seems that it's has all the symptons of the 35R wave plate issue and referred me to technical technical bulletin 14404. The service manager said this is a known problem with this vehicle (and many others from the 2007-2009 time frame), to Google it and I'd find lots of posts/info on the issue.

I then checked my files and came across a service bulletin I received in March 2015 from GM saying that that my vehicle could experience a cracked or fractured wave plate and loss of 3rd, 5th and reverse gears (totally forgot about it). The affected vehicles have the 6T70 and 6T75 "FWD" transmissions. My vehicle is an AWD. The bulletin also says GM was extending the warranty to 10 years or 193K Kms (whichever occurs first) and the condition will be repaired at no charge to me. Online they seem to have expanded it to some Saturn vehicles and the AWD as well. - http://gm.oemdtc.com/1870/14404-tra...-2007-2009-buick-chevrolet-gmc-pontiac-saturn

I spoke to the service manager again and said I had received the letter from GM. He asked to bring it in, they'd copy it and attach to the work order and when they crack the transmission and discover if it is in fact the a cracked/fractured 35R wave plate, it would be covered under the extended warranty. That was the good news of the day.

Fingers crossed that it is in fact this issue. I had all symptoms pretty much everyone else had that posted about the same problem happening to them.

Anyone else on this site experience the same with theirs? Any issues after the replacement? I read it needs a fairly large teardown to ensure no other damage and a thorough cleaning as small particles/filings could get left behind and cause the issue to reappear. It's only like a $10 part but the bulletin says about 16 hours of labour! The service manager said their shop has worked on a number of Acadia's, Enclaves, G6's and Equinox's that had the problem (even his had own replaced in his old '08 Acadia after breaking around 80K). He said this is the first Torrent GXP that has come into their shop but I don't think they've sold many in my area (at least I haven't seen many on the road over the last 7 years).

The vehicle has been pretty good for us, no major repairs has only 114K Kms on it and was hoping to get another 50K-100K Kms. Knock on wood!
 
Obviously cannt speak for everyone but I believe you are the first to mention this in such detail. Is the repair they are performing covered for up to 10 yrs. or 193KM from the date of purchase? Thanks for the post.
 
Obviously cannt speak for everyone but I believe you are the first to mention this in such detail. Is the repair they are performing covered for up to 10 yrs. or 193KM from the date of purchase? Thanks for the post.

The garage hasn't opened the transmission yet to confirm it is in fact the 35R wave plate failure. Their transmission guy is off until tomorrow so he said they should get to it tomorrow am. Although the service manager did say my explanation of the problems right before it failed, the fact there is no reverse gear anymore and the codes the bulletin says would be thrown matched pretty much what others had encountered who had the same cracked 35R wave plates they've seen in their shop. He's pretty sure that's the problem but will not confirm until they open it and look.

I don't know if the warranty will be reset and covered for another 10-years or 193,000 Kms. The letter does not give that detail. I will ask the dealer this question if in fact this is the issue and it will be fixed under the current extended warranty service bulletin and find out what kind of warranty comes following the fix.

I you Google wave plate failure you'll find tons of threads on the issue (mostly with Outlooks, G6's and Acadia's). There is even mention of it in this wiki article specific to the transmission - https://en.wikipedia.org/wiki/GM-Ford_6-speed_automatic_transmission

...It was also used for the Pontiac G6 GTP models and the GMC Acadia models for 2007. Prior to 2009, this transmission had issues caused by a very weak 3,5,R wave plate, which made this transmission prone to failure in GM products. Updated wave plates were released for many clutches in 6T70. The old design wave plates weren’t stress relieved and could break with use....
 
Please keep us updated on how things work out for you, good luck.
 
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