Chevy Silverado Transmission Control Module

dlw930

Well-known member
Had the transmission control module replaced last week on my 2011 Silverado 3500HD 6.6L Duramax/Allison. At first, Chevy service guy thought it might be covered under 5 yr power train warranty, but discovered it wasn't. Ok. I paid nearly $800 bill and took off poor but happy truck was working good again.

THEN, I looked in my warranty manual under emission warranty parts list and there was "Transmission Control Module" with "**" after it, meaning part covered for 8 yr/80,000 mi. which I'm under. So, called servicing dealer. They say "no" their computer says part not covered for my VIN b/c more than 50,000 mi. and 8/80k only applies to 2010 and older trucks. I tell them it's in my 2011 model book in black & white and I'd be happy to come show them. They said call GM warranty claims, so I did. First guy I talked to was same as dealer service..."no, no, no truck had more than 50k miles." I asked to speak to his supervisor and talked her into looking at the same 2011 Warranty Manual that I was looking at. She saw what I was seeing and asked to put me on hold while she called dealer SM. She agreed with me that the manual indicated the part was covered, but said the information on the GM computers was unclear or confusing at best. While talking to her, I got voicemail from dealer SM saying it looked like they were in error and the part and labor is covered. He is figuring out how to get reimbursed and reimburse me. It looks like I made almost $800 for the hour I spent reading the manual and making phone calls today.

Maybe this will help other truck owners to check their warranty manual before paying for service of this type.



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TravelTiger

Founding Texas-West Chapter Leaders-Retired
Great to hear. Just to have it here, what were the symptoms you were experiencing that led to this repair?
 

dlw930

Well-known member
Initial symptoms showed up as I was dropping our Landmark at a KOA site in Ohio. Main symptom was truck not shifting into gear when I depressed brake pedal and moved shift lever. It was weird; the small line that normally appeared under each letter indicating P, R, N, D, M, etc. didn't appear. Sometimes, it would shift into gear but wouldn't shift from 3rd to 4th (engine speed would stay between 2000 and 2500 at 60 mph when it normally would have shifted and dropped to 1500-1800 rpm at that travel speed.)

This was a Sunday late afternoon, so I was going to either drive it or have it towed to nearest Chevy dealer Monday a.m. When I started the truck Monday morning, it behaved normally, so I drove it the 4 or 5 miles to the nearest Chevy dealer who couldn't get to it for at least 2 weeks even to check error codes so I left to go to next closest dealer 12-15 miles away. As soon as I pulled onto the street and started accelerating I could tell it wasn't shifting again and line under "D" disappeared. I should mention that the check engine light (not flashing) also came on during the times of not shifting, but the service tech determined this was due to bad NOX and DEF sensors which they replaced under the emissions control warranty without question.

Sorry for the long explanation, but it was all very strange. I told my DW early on that it seemed like a computer or sensor issue and not a mechanical failure. At least it happened while we were in a campground where we planned to stay for several days and didn't have to make major changes to our plans. . There's more to the story, but that's enough for this venue. I'll save the rest for over a beer at a rally somewhere.


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Bob&Patty

Founders of SoCal Chapter
NOX and DEF sensors both bad at same time? Maybe and lets just leave it at that for now. Trans control modules do go bad....but it sounds to me like the switch on side of the trans went bad. That switch is what controls the "PRNDL" (tech term) readings on the cluster. the switch also talks to the trans control module and the ECM. I have replaced many switches and shift cables for this issue, but not many modules.
 

dlw930

Well-known member
NOX and DEF sensors both bad at same time? Maybe and lets just leave it at that for now. Trans control modules do go bad....but it sounds to me like the switch on side of the trans went bad. That switch is what controls the "PRNDL" (tech term) readings on the cluster. the switch also talks to the trans control module and the ECM. I have replaced many switches and shift cables for this issue, but not many modules.

I thought it was pretty strange that the NOX and DEF sensors both went out at exactly the same time as the TCM. Although I had the NOX and an exhaust temperature sensor go bad within 3 days of each other last year. The truck seems to run fine now, so I'm not second-guessing their replacement of the TCM. All of the components on the ECS creates a reliability nightmare though; keeps service techs employed, I guess.


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Bob&Patty

Founders of SoCal Chapter
Had 3 GM trucks since 2005 and never had any issues with the things you are. My 2013 has been the best of them so far. You must be hard on them ..LOL.
 

buddyboy

Well-known member
I thought it was pretty strange that the NOX and DEF sensors both went out at exactly the same time as the TCM. Although I had the NOX and an exhaust temperature sensor go bad within 3 days of each other last year. The truck seems to run fine now, so I'm not second-guessing their replacement of the TCM. All of the components on the ECS creates a reliability nightmare though; keeps service techs employed, I guess.


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Our son is a master mechanic and he despises all the electronic components on vehicles. He says he's seen so many times one component failing leading to another and another. He gets concerned that the repetitive trips for repair can give people the impression that they have been set up. Causes some unnecessary stress for everyone.
 

Bob&Patty

Founders of SoCal Chapter
Yep me too. Was a GM tech for over 45 years. Electrical things fail all the time. A good dealership will only replace what is needed.....others not so much. Some will take advantage of someone stuck and from out of town. If you think you have been HAD....contact the BAR and have them investigate. Also, always ask for any parts that you pay for. By law they are yours to keep just in case there is dispute.

David, BTW, my personal opinion that $800 is a lot for a trans module. It is not hard to get to. My '13 is on the drivers bolted to the core support. Takes about 10 minutes to connect the scan tool and diagnose the problem.
 
TCM failed in my 2012 2500 HD with 41k miles on it. Dealer told me not covered under my remaining power train warranty and quoted $1200 to replace.

Before going down to pick up my truck and pay the bill I Googled "Transmission Control Module Chevy Silverado" and those keystrokes saved me $1200 because that's how I found your post.

Long story short I got pretty much the exact treatment from the dealership as you did....even after I showed them the manual....ridiculous. After half an hour of dancing with a Service Advisor he finally called the Service Manager who eventually approved this as a valid warranty claim.

THANK YOU for taking the time to make your post.....you did a complete stranger a huge favor!
 

dlw930

Well-known member
TCM failed in my 2012 2500 HD with 41k miles on it. Dealer told me not covered under my remaining power train warranty and quoted $1200 to replace.

Before going down to pick up my truck and pay the bill I Googled "Transmission Control Module Chevy Silverado" and those keystrokes saved me $1200 because that's how I found your post.

Long story short I got pretty much the exact treatment from the dealership as you did....even after I showed them the manual....ridiculous. After half an hour of dancing with a Service Advisor he finally called the Service Manager who eventually approved this as a valid warranty claim.

THANK YOU for taking the time to make your post.....you did a complete stranger a huge favor!

I accept donations! LOL. Seriously, I'm happy my post helped you. That's what this forum is all about!
 

lynndiwagoner

Well-known member
Very interesting. Last summer my 2011 TCM failed during a trip, truck has 90,000 miles. Code indicated that the neutral start switch (which has been moved inside the transmission) was bad. Towed to dealer where they started off by changing the switch, which didn't fix the problem....it was under warranty. Dealer called Chevy and they suggested changing the TCM, which DID fix the problem. I had done a lot of reading on the TCM warranty and determined that it was not under warranty so the cost was $900.00. I called Chevy and talked to them and told them I could get a new TCM off of Amazon for $250.00, they had charged me $500.00. Chevy called the dealership and after a while the dealership rebated me $200.00. I've since had both NOX sensors go bad. Chevy has extended the warranty on these as they were a problem on the 2011 engines so they were done under warranty. The TCM module seems to be a problem on the early LML models. You were lucky.......
 

jayc

Legendary Member
When I had my 2002 GMC 2500 the PRNDL valve (dealer term) went out. No fun driving on the freeway in Houston in 2nd gear! It was out of warranty due to mileage and if I recall correctly, it cost me about $400 to repair.
 
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