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TCM Transmission Control Module???

293K views 188 replies 86 participants last post by  Kaheverly 
#1 ·
Took my truck in after some issues it was the TCM.

What would cause this to go bad???
Also
What can be done to prevent in future???

Thanks Y'all


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#3 ·
I had an 11 that had tcm failure, I think it would stay in 4th would not shift up or down could not use it in manual mode, there were more issues also. It was replaced under warranty. No reason was given for the failure and no way to prevent it.
 
#4 ·
I had my TCM replaced just a couple weeks ago. Mine's an '11. It was starting to freak out a little here and there. Symptoms were rough shifts, wouldn't down shift to 5th from 6th on the freeway when trying to pass, and occasional slipping. It just gave out on me completely on the freeway and locked in 5th gear. As you said, no manual shift and lost the gear indicator on the DIC. My TCM was replaced under warranty as well, and the truck now runs great and acts as expected.
 
#6 ·
they warrantied it even tuned and deleted??
 
#5 ·
Mine was replaced at 7500 miles. No warning at all, just dropped to 4th and stayed there and lost shift indicator lights, and traction control and stabilitrak warnings came on. I have almost 36k on it now and no problems since with the replacement TCM so who knows.
 
#7 ·
When mine failed it there was no warning signs, I shut the truck off everything was working and when I started it up it quit. Same as you said, stabil track and traction control warnings auto door locks quit stayed in 4th.
Had to drive home 60mi then to the dealer 40 mi who after they diagnosed the problem sent me home with it while they ordered the tcm ?? then back to the dealership. In total about 220mi at 40 mph. Not good:help
 
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#9 · (Edited)
You guys got lucky. When mine quit last week, it locked in park while I was still driving. Just like stepping on the parking brake. Luckily I had made it into the parking lot, and was not at highway speed. They told me it was not a hard part so was not covered under power train. I am still within the three year window, but am out on miles for bumper to bumper.

*****Update*****
After reading the comments about the Federal Emissions Warranty, I looked in My Warranty Manual. Sure enough, there it is. Covered to 8 years/80,000 miles. I took the book back to my dealer and showed them. They were unaware as this does not automaticaly show up on the warranty program they use. They gave me a full refund of what I had paid and appoligized for the inconvenience.

Thanks to everyone who suggested this.
 
#18 ·
I had this same luck, locked up on me and left me stranded in the road. Let's just say the people behind me at the stop light were very happy i wasnt moving when the light turned green but all i could do was wave Heyyaa .

I took mine to the dealership next to my house becuase i wasnt sure if i could make it to my uncle who is a chevy mechanic at another dealership. The dealership by my house wanted swindle me out of every dime i had. 500+ for the part and another few hundered for the labor i was looking at almost a grand to fix. I politely decline. Dealer cost for the TCM is only around 300 bucks if i remember correctly.
 
#12 ·
Mine gave out at like 45K.... basically got stuck in like 4th and I limped it to work and called the dealer.. fixed under my "extended" warranty.. lol
 
#13 ·
Anyone have any educated guesses on what the problem could be with these? I don't ever remember hearing about TCM issues on the older trucks, and I certainly never had an issue on my LBZ.
 
#14 ·
Never realized so many have had TCM issues until now. What's the damages to replace one of these if out of warranty?
 
#15 ·
Looks like one of the local dealers has it for sale online and they show it as $553.34. I can post the link if anyone is interested.
 
#24 ·
I use synthetic TCM fluid. Makes them last longer.

Just need to change my muffler bearings and top up with halogen fluid.
 
#27 ·
Finally got my truck towed to the dealer Monday for them to diagnose my issues which I knew was a faulty tcm. And mid day Tuesday they called and said "turns out it was your tcm". On the phone and in person I explained that there was an issue and I'm one of many with a faulty tcm. They insisted I prob had had a loose connection or an open in my harness somewhere... They said $750.39 to fix it and it would be done tomorrow. Also said the warranty would not cover it because I have 54,125 and it's only good till 50,000. And because I have an h&s mini max full delete. However my extended warranty will cover it for $108. After arguing for a bit about the federal emissions warranty and how it clearly states 8year/ 80,000mi he said that's only for little cars like the cruze not diesel trucks lol. So I agreed to pay $108 and it would be done the next day wed. After hearing nothing I called in Thursday and was told it's on back order with no idea when it will be in. Good thing I have 3 motorcycles...
 
#28 ·
Warranty booklet is clear.

8/80000 on the TCM in the emissions warranty section.

Talk politely to the GM number in your OM and warranty booklet.
 
#29 ·
Seems like the 2011's are doing it more than others.. they should put out a TSB on it or something..
 
#30 ·
Im a manager at a chevrolet dealership so i just want to throw this out here.

Below is a screenshot of your owners manual emissions warrenty coverage, which i didnt know TCM's were listed. Which seems strange to me but anyhow if your vehicle is completely stock and in the stated time/mileage its covered. If your dealer says otherwise go to another dealer or call/email someone higher up. If you trucks modified in anyway and they can prove it its completely up to the service manager at that dealership.






 
#32 ·
TCM Failure
Ok so here is the situation. Got service stabilitrack and all those messages last week on my way to work. Gear shift indicator dissapears no trans temp, and cel. Trans is now in failsafe, no biggie. Get to the first stop light and no go. I get moving enough to pull into gas station. Check cel, loss of communication with tcm u0101. Shut her down, get out check connections and fuses. Try again, no go. Hit onstar button, and what a bunch of bs. Onstar is going to be canceled later today. Finally get in touch with Chevy Roadside assistance. 20 min to find a tow, and almost 3 hours to get the tow truck there. No biggie once tow was scheduled got a ride to work, left keys in it for tow driver, not like it was gonna go anywhere anyways. Finally nearest dealership calls, tells me "Yep you have a trans problem, we don't work on Allisons. You gotta call Allison" Call Allison, and and informed about service agreement with them and chevy. Call dealer back and was informed "Allison must be wrong, we've never worked on an Allison." At this point I'm becoming a bit irritated. They also said "Even if we did work on Allisons, it'd be a few weeks before we could even get to it." Why did Chevy roadside people decide to tow me there? I'd be totally understanding if the dealer said that they didn't have anybody qualified to work on an Allison. But they flat out refused to. So I get a hold of my local dealer which I''m not all that fond of but they said Yes we can fix it might be after the weekend before we get to it but bring it it. Mind you this was July 2. Get a tow referral from dealer and get in touch with them, wasn't too concerned with when it was gonna get there. Tow driver was there within an hour and a half, 75mi to pick up. Get it towed to local dealer on my $350 for 75 mi tow to dealer. Dealer calls next morning July 3 they had a chance to look at it. TCM fried due to Static Discharge. I said what could cause that? TSB about Aftermarket fan belt causing excessive static buildup and discharge to fry TCM. Used a Goodyear gatorback belt not a cheapo. And it had already been on for 50K 1year 3mos. Dealership says they have parts ordered. Now I gotta pay dealership to change belt too. Stop by to get some stuff outta truck for work and talk to service advisor and get TCM should be here on monday. Walk back to truck and bs with tech a few min, he says might be a week or 2 or who knows, TCM backordered. Now WTF I'm getting a little more pissed. Last time I was at dealership for DEF pump they couldn't even get one, with no known availability. Delete done then, just outta warranty then. Does Chevy think their vehicles don't break and don't stock any parts? 2 break downs and parts not available either time. Oh getting back to first dealership, I ask what I owed. Told nothing, that was a surprise. But they also wouldn't give me any paperwork saying vehicle was looked at or was even there. So what I want to know is, can I go back at original dealer for tow to second dealer? Why the hell would they flat out refuse to repair Allison that Chevy is contractually obligated to fix. Why would Chevy have my truck towed to a dealer that wouldn't work on it. There has to be a record of tow to there through chevy roadside. 150K on truck now.

So I call dealer this morning to see if they know when they will have TCM. Oh yea we have it, do you want to make an appointment to bring truck in. I say why do I need an appointment you have had my F***ing truck for over a week. Service advisor asks who my service advisor is, and I say It's you thats why I asked to talk to you, "Remeber I'm the poor bastard that had to have his truck towed from another dealer in Chicago." I get an "Oh yea" Oops "Looks like your TCM should be here first of next week" Hmm, same answer I got a week ago. Increasing Irate now. So I order TCM online, I sure hope they get one before I do, or I'm gonna lose my shit.

Make sure you only use OEM belts. Don't want it to cost anybody else $1600 for tow, belt, and TCM. Not to mention rental that I'm paying for.


Can one of you GM Customer Service people contact me. As I am not happy at all with 1 of your dealerships. And not impressed with a second dealer or your roadside assistance. I'm only 30 now, it'd be a shame to lose 40+ more years of $50k every 4 years or so of vehicle purchases from me.
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2011 LML Crew cab, short bed, 6" oval steps, line-x bed and wheel wells, undercover se
H&S Black Maxx, 4" Flow pro downpipe back
 
#34 ·
Just ordered mine today.. Said would be a week 😠
 
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