GMC Acadia Forum banner

41 - 60 of 137 Posts

·
Registered
Joined
·
84 Posts
So I completed this repair last weekend with mixed success. Two of the membranes on the TCM were ruptured (See pics below). This seems to have fixed the "Stuck in First gear issue".

However I was hoping this repair would also address the delayed and non smooth engagement into "Drive". No change there it seems. Transmission otherwise smooth shifting and no signs of metal or debris when I drained the tranny.

So I'm at a bit of a crossroads - some folks claim this is caused by the TCM as well but others say they've replaced the TCM and the delayed engagement to drive persisted. Do I just live with this issue or bite the bullet and buy a new or Doorman refurbed TCM?

BTW....I applaud the OP who completed this repair in 4 hours....its was more like the 10-11 hour range for me. I can't imagine completing the repair without removing the airbox first either. On the Outlook its held on by one bolt, one torx screw, and a grommet. Then you have to do some fiddling to get it out around all the various lines that are there. Alldata DIY also suggests disconnecting and removing the ECM for this but I didn't have to (and the electrical connectors on the ECM seem pretty tough to open without breaking them).

I would definitely classify this repair as being more involved than replacing brakes and rotors for the amatuer DIYer - but if you have time and patience you can do it. Seemed like every bolt and electrical connector wanted to fight you to take more time - lots of blind work behind cross members / other bolts etc and a real treat to try and put a torque wrench on when re-assembling.

Some pics from the repairs:

Air Box Removed, Cover partly off:
https://photos.google.com/share/AF1QipOmoAMkpbMxCf60uBIdPzi77mjmMRJrqEDmd85Bxqj7clifXyQkU_k_AcogxcMq0w/photo/AF1QipPpdKLPogbqOkDxLj-Pj9mWDfvK1IJLeygJtTES?key=dGxCczdWZkpXdHYzWERvcl92WGI4cWhid3h2bUpB

TCM and bolts:
https://photos.google.com/share/AF1QipMqrubHpv8K3JVGpVpRk0QbmEflPIJFm77Gjx-ZK4Qg88BYefH0s8uMWDG2cUvAeA/photo/AF1QipNvnjeK6JtuGLuwWjo7bYWFJfHt3JKNL7A-Pue0?key=ajRsRzVJTVVQX2NPdU5wZUM0czVlZXZ6OTZFN0JB

Two broken membranes:
https://photos.google.com/share/AF1QipMqrubHpv8K3JVGpVpRk0QbmEflPIJFm77Gjx-ZK4Qg88BYefH0s8uMWDG2cUvAeA/photo/AF1QipPO3aEQ2GAWrODH9YESlGcdF9WZogQtvHR2KPTm?key=ajRsRzVJTVVQX2NPdU5wZUM0czVlZXZ6OTZFN0JB

Repaired membranes:
https://photos.google.com/share/AF1QipMqrubHpv8K3JVGpVpRk0QbmEflPIJFm77Gjx-ZK4Qg88BYefH0s8uMWDG2cUvAeA/photo/AF1QipNN2lb7-NeVshPE39owASSn3vy_q6M42R4VTFGw?key=ajRsRzVJTVVQX2NPdU5wZUM0czVlZXZ6OTZFN0JB

Sonax Repair Kit:
https://photos.google.com/share/AF1QipMqrubHpv8K3JVGpVpRk0QbmEflPIJFm77Gjx-ZK4Qg88BYefH0s8uMWDG2cUvAeA/photo/AF1QipOhVZ8zcJ0ZF_04wWIyv1vNacOvenT0iBKI-Yop?key=ajRsRzVJTVVQX2NPdU5wZUM0czVlZXZ6OTZFN0JB

Tranny with TCM and Cover removed:
https://photos.google.com/share/AF1QipMqrubHpv8K3JVGpVpRk0QbmEflPIJFm77Gjx-ZK4Qg88BYefH0s8uMWDG2cUvAeA/photo/AF1QipOvsMGVkAU0E3Gfa72F8jjvGMa6xaCy-P-PKwja?key=ajRsRzVJTVVQX2NPdU5wZUM0czVlZXZ6OTZFN0JB
 

·
Registered
Joined
·
1 Posts
So I had the same problem on my 08 Acadia. Vehicle went into limp mode with a po752 diag code. I followed stpete's steps to fix mine as well (thanks by the way). I opted to do the rebuild kit. I found the kit on ebay for $48.95. When I pulled out the module I had 2 laminate discs that were popped out. Since the kit came with 5 I just replaced them all. Really wasn't a bad repair to do. Acadia is running great now and shifting great so far.
 

·
Registered
Joined
·
4 Posts
So my TCM is really getting bad now. Throwing codes every other day now along with the stupid safe mode one gear BS. I just ordered the membrane kit from Ebay. It looks like it also comes with the installation instructions that you're referring to needing the subscription on Alldatadiy.com (btw if you do need a subscription use AD10VP on coupon code for 10% off). Hopefully I can get this in next week because I have a lot of driving to do the last two weeks of this month. I tried to trade this car in yesterday, but they wouldn't give me crap for it. I guess I'm stuck with this turd. Thank you for this forum because without it I would have taken that much of a loss.
Ebay kit search for - Sonnax Pressure Switch Installation Tool Kit for GM Transmissions 6L80 6L90 6T70


:facepalm:
 

·
Registered
Joined
·
122 Posts
Outlook Guy:
Your images are not shown here. One of ways to have your images visible by uploading your images on a free photobucket website then insert the image links on your posts.

HD
 

·
Registered
Joined
·
84 Posts
hungtdao said:
Outlook Guy:
Your images are not shown here. One of ways to have your images visible by uploading your images on a free photobucket website then insert the image links on your posts.

HD
Thanks for letting me know. I've converted them to hyperlinks as google doesn't play nice with embedded photos in this forum (they show only for me apparently) and I don't want the hassle of moving photos around to other providers.

The repair continues to be solid. As an added piece of info - the secondary "delayed shift to Drive" issue resolved itself a couple weeks after the repair was completed so I'm kind of wondering if the TCM had to re-learn with functioning switches after the repair.
 

·
Super Moderator
Joined
·
18,287 Posts
Outlook Guy said:
... google doesn't play nice with embedded photos in this forum ...
I looked at your pics. Seems 'google photos' doesn't give any sharing options, unless there's no way an outside viewer could get to them. All I found was an option for 'slideshow' or 'download.' Just putting the web address of a pic inside an 'insert image' command hardly ever works with anything. (the pics are good, btw)
 

·
Registered
Joined
·
122 Posts
First, I would like to thank all contributors to this discussion. It extremely helped me to make the decision to do this hassle job with less pain. Yet it saved a lot of $ for this simple issue. Since the instruction has been posted by other members, so I don't want to repeat again. I just want to share some hints that, in my opinion, may help easing your job. Everyone has different ways. So, DIY with your best judgement. It took me about six hours with a friend help. Removing the air filter box is the most hassle job and time taken.

  • 1. Since it is a hassle job, you don't want to see your transmission leaked after doing it. So, when ordering your Sonnax kit, I highly suggest to order the seal + gasket as well. They cost less than $15. The ACDELCO 24216446 Transmission Valve Body Cover Wiring Connector Hole Seal, ACDELCO 24229593 Transmission Valve Body Cover Gasket
  • 2. I safely jacked up my Acadia then remove the driver's front wheel. Remove the splash cover that helped to easily access those bottom screws of the TCM. Have a step ladder or a chair, so you can work on the top.



  • 3. Remove ECU helps to clear some electric cords prior to remove the air filter box.



    Those connectors are not really hard to pop out if you do it the right way. First pull up the orange lock, then use your finger to push down while pulling up the locking arm as shown in the images:






    • 4. Remove the TCM main connector



    • 5. Again, removing the air filter box took most of total time. Not only it has many torx nuts. If you don't clear all electric cords and other cables out of the way, NO WAY, you can take the box out easily. Highly suggest to take a picture before you remove the air box, so when you put it back in, you would know what cords/cables/tube should be on which side, or top, or bottom of the box. The picture shows the air box has been removed prior removing the TCM. I also removed the air intake tube and the engine's top cover to get more working space.



    • After the TCM cover is removed:


    • After the TCM removed, there are 5 different size of screws to be located. Four long screws on the right are 8mm head, all other are 10mm head.


    • Mine has two broken laminate discs. The picture shows the TCM after replaced with new discs (membranes) and seals before put it back in.

    Well, it drives and shifts smoother now. Hope it will last for a little longer. It happened on my Acadia with only 86k mileage. With the hot fluid and condition inside the transmission, the type of material made for these pressure switch discs (membranes) are not impressed to sustain such a hot and pressure condition.
 

·
Super Moderator
Joined
·
18,287 Posts
Very good, hungtdao! :thumb: Congrats on your success. Thanks for the additional insight.
 

·
Registered
Joined
·
1 Posts
Thanks to all for the great posts. 3 weeks ago I did the swap with a reman TEHCM in my wife's 2008 Acadia. I strictly followed the directions to read/write using the software transfer tool and transmission was running good after I was done :)

Initially the tranny worked fine, but recently on the highway, the tranny downshifted from 6th into 5th when on flat surface or going downhill about 5 separate times. The car has 93k miles and never had this problem prior to installing the reman TEHCM...

Specific symptoms:
No check engine light came on at any time
After tranny shifted itself into 5th, sometimes it would go back into 6th after 20-40 min of highway driving, sometimes it stayed in 5th.
If the car wouldn't return to 6th, when slowing down to pull over, the downshifts into 4/3/2/1 are at low (<1000) rpm and were harsh.
After turning off engine for 10 min and restarting, the tranny would behave normally (at least for a while)
When in 5th at 75-80mph, I took my foot off the gas for 5-10 sec but it would not shift into 6th. Same if traffic slowed to 50mph and returned to 75-80mph
When malfunctioning (in 5th gear), putting the gearshift into manual mode would downshift the tranny into 4th, I could then upshift to L6 on the DIC. The car would upshift to 5th but would not enter 6th.

I read that a high TFT would cause the shift into 5th, but high TFT is unlikely as we haven't had wave plate failure in this car (yet) and the transmission was flushed at 90k miles.

Any ideas - possibly a bad electrical connection, a leak in the gasket between the TEHCM and transmission, or just a bad reman TEHCM (Dorman says they check them prior to shipping but an intermittent problem may pass?). Should I try to re-program the TEHCM, how to do this without a transfer tool? Any help is appreciated.

Mike
 

·
Super Moderator
Joined
·
18,287 Posts
mofat27 said:
...
Any ideas - possibly a bad electrical connection, a leak in the gasket between the TEHCM and transmission, or just a bad reman TEHCM (Dorman says they check them prior to shipping but an intermittent problem may pass?). Should I try to re-program the TEHCM, how to do this without a transfer tool? Any help is appreciated.
If you're confident in your work, you should call Dorman and see what they want you to do. It could be they sent you a defective part. Someone else had a problem with a bad replacement TEHCM and Dorman was very good at taking care of them.
 

·
Registered
Joined
·
63 Posts
Speleos said:
If you're confident in your work, you should call Dorman and see what they want you to do. It could be they sent you a defective part. Someone else had a problem with a bad replacement TEHCM and Dorman was very good at taking care of them.
I had a defective TECHM from Dorman this summer. The first one worked fine for a few days and then started shifting hard and threw the same codes. They sent a replacement and it has worked out fine. I saw nothing wrong with the screens with the first one they sent so I'm assuming it was something internal with the TECHM that caused it to be defective. I had purchased mine through Summit so there was some issues getting my core charge back but after a few phone callsto Summit and Dorman, that issue was resolved.
 

·
Registered
Joined
·
9 Posts
So I got something like this tonight. Truck is stuck in gear and is throwing the 0700&0752 codes. I've read through the article and am going to attempt the repair. Would you all recommend the dorman trans control module or could I just do the sonnax kit?
 

·
Super Moderator
Joined
·
18,287 Posts
JosefLillo said:
So I got something like this tonight. Truck is stuck in gear and is throwing the 0700&0752 codes. I've read through the article and am going to attempt the repair. Would you all recommend the dorman trans control module or could I just do the sonnax kit?
Is the fluid at the proper level? Is the fluid clean? Is the solenoid truly stuck? Is it just a failure of the laminate disk(s)? What you replace would depend on what's wrong. These questions must be answered before you make a determination of the best way to remedy the problem.
 

·
Registered
Joined
·
9 Posts
Ok I understand this is my daily driver and I would need it fixed ASAP so I'm good with just replacing the whole unit then just want to make sure this is the right repair for the job. Reset the computer today and checked the level and cleanliness of the fluid and it all checked out ok. I may have to get the part out first then see if I want to take the sonnax route or not.
 

·
Registered
Joined
·
122 Posts
I have chosen to go with Sonax as I don't have to worry about receiving an incorrect programmed module. Second, since it is my car, most owners who have mechanical or handy-man mindset, normally take time and be more careful when DIY job. Of course, it is your choice, if you are not sure that you can replace new discs properly and want to stay out of hassle then simply buy a new TCM. I would buy a new one if there is a redesigned TCM available with different type of discs rather than laminated. I still cannot understand why engineers, who designed this TCM, did not use more durable material such as aluminum or even better with titanium discs.

Update: on Dorman Website, it claims that its remanufactured TEHCM using a different material discs rather than the OE material. So, I guess replacing a remanufactured TEHCM is probably a better choice. The only difference is $50 vs. $300.
 

·
Registered
Joined
·
1 Posts
I believe I am having the issue in play here and am about to pull the trigger on the repair kit. My Outlook will go into the "shut down" mode discussed here. When it does this, along with the CEL, the brake check lights come on, the emergency brake light comes on, and on the dash displays "All Wheel Drive Off". I didn't see anyone mention this and wanted to check if anyone also was receiving these lights along with the CEL? I took to the dealer to diagnose several months ago and they said they weren't entirely sure, but that they would first try replace the Brake Control Module (~$800), and if that didn't work the would then do the Transmission Control Module (~$1,200). Can anyone confirm they were receiving these lights on their dash when the problem was occurring?

I have been able to get by so far by resetting the battery, but I'm sure that trick will only work so many times.

Thank you.
 

·
Registered
Joined
·
1 Posts
Thanks for the info stpete, great pics too. I decided to take a crack at replacing my TCM module as well on my 2008 acadia and had a question. Do you keep the original TCM module on the car and run through the programing Dorman products.com has you run through with the software transfer tool? Or, can I remove my original TCM and provide the person I purchase from my VIN# so they can program, and when it arrives I can just install the new one.

Any help is appreciated!
 

·
Registered
Joined
·
122 Posts
Mine only have TEHCM module code shown up as my transmission stuck running on the first gear only. If the CEL does not show TEHCM code and your transmission shifting fine, then I don't think you should replace TEHCM. I updated my previous comment that replacing the TEHCM is probably a better choice. I saw on the Dorman Website has claimed that its remanufactured TEHCM using a different material discs rather than the OE laminated material. Yet, there is only a faction of the cost $50 vs. $300.
 

·
Registered
Joined
·
4 Posts
First post here (I think). Not sure where the vehicle info is supposed to be for it to post with my reply..

2008 Acadia 2WD. Bought used in 2013 with very low mileage (<60k). Didn't know about the wave plate thing until afterward, but thankfully no major issues yet (>180k miles).

"Flushed" (drain/refill, drain/refill) the tranny fluid last June, after she started noticing a delayed shift into Drive (from any other gear, no other symptoms or codes). Didn't work, so used the extensive and informative write-ups here, along with a subscription to AlldataDIY, to replace the pressure switch membranes last weekend. Like many others here, not nearly as bad as I was anticipating (just under 6 hrs). Two of the membranes were totally blown out, and a third was cracked and just about ready to go. Changed all four since I was in there.

Just one comment and a couple questions:

First, pretty sure I remember a 12th bolt holding the techm to the valve body vs. the 11 that Alldata references. Middle top, and a short one (<42mm). Only reason I'm thinking so, is because I removed them in order, labeled them, and still couldn't get the techm out. Had to loosen/remove one more bolt.....counted 12 of them on the floor.

The questions are mainly for OutlookGuy, since he was the only one with what seems to be the same issue (minus the stuck in 1st). I do see where you said that the delayed shift cleared itself after a couple of weeks, but you also said it was rough immediately after.....did you clear all the stored codes? And, was the delayed shift persistent, every time? I have been driving her car when it will shift directly into drive without hesitation, seemingly when cold, but not reproducible on demand.

Just waiting it out, now, I guess.
 

·
Registered
Joined
·
30 Posts
A question for anyone on here, I am experiencing a jerky shift every once in a while seems to be related to the engine being warmed up and outside temperature being up, which it struggles to sometimes this time of the year in Minnesota. Therefore probably once the fluid viscosity has dropped a bit due to driving for a while and warming the fluid up. I had the 3-5-R replaced around 65k and I'm at 133k now. I have not managed to get any type of code yet on the vehicle to come up. So... I am hopeful that this TCM is what needs to be replaced and if so I hope to just get the Dorman remanufactured part.

Does it come with the gasket/filter that goes between it and the valve block? I realize it doesn't come with the connector and cover gasket so I'll plan to get those. If it doesn't come with that gasket, should I hunt to find that gasket too? or just use the original one in there?

The jerky shift feels like it is trying to go into gear, but goes into neutral then feels like dropping the clutch on a manual transmission. Seem to be 4th. gear or somewhere around there....
 
41 - 60 of 137 Posts
About this Discussion
136 Replies
44 Participants
speleos
GMC Acadia Forum
Join our Acadia Forum community where enthusiasts discuss mods and troubleshooting for the GMC Acadia and Denali Crossover SUV.
Full Forum Listing
Top