11' Denali problems, possibly TCM???

Dtrickz

New member
Sep 19, 2016
3
0
0
So I had the Shift inhibited message one day and the truck wouldn't go into any gear. After sitting awhile it started working fine again. Next day I added some tranny fluid because it was low, took the truck around the block and it was shifting ungodly hard up and down. The next day it was back to normal again so I drove it around the block a few times to get the tranny up to temp. Tranny fluid checked out good so I turned the truck off. I pulled the plug on the transfer case and fluid level in it seemed good. Started the truck up about 30 minutes later and it wouldn't go into gear again, was showing the shift inhibited message again. When I shift out of park you can hear the tranny/driveshaft click like its going into gear but it won't move. Does the same thing in 4hi and 4lo. I unplugged the TCM and plugged it back in and still nothing. Also while truck is in park it seems like its idling high to me and about once every 20-30 seconds it kicks down for a split second as if something is trying to kick in, almost like turning the AC on. Has anyone that has had to replace the TCM had these symptoms? Or can someone point me in the right direction? Also truck is throwing no codes. Any help is greatly appreciated
 

IOWA LLY

Yes, its really me
Feb 23, 2007
2,275
4
0
Sounds like typical fried tcm. Seems way to common on the 11 and newer trucks lately.

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Dtrickz

New member
Sep 19, 2016
3
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I had a buddy put his snap on scanner on it and pulled these codes
p0711-tft sensor
p0741-tcc
p0729-incorrect 6th gear ratio
p0894-transmission component slipping
p0571
p0851
Truck drove fine this morning and after sitting outside in the sun it wouldn't go into gear again. Took the TCM inside and let it cool down, plugged it back up and it worked fine. Im leaning toward the TCM now but just trying to make sure before i spend a few hundred
 

A. Stock Lbz

New member
Aug 13, 2013
342
0
0
spokane wa
I had a buddy put his snap on scanner on it and pulled these codes
p0711-tft sensor
p0741-tcc
p0729-incorrect 6th gear ratio
p0894-transmission component slipping
p0571
p0851
Truck drove fine this morning and after sitting outside in the sun it wouldn't go into gear again. Took the TCM inside and let it cool down, plugged it back up and it worked fine. Im leaning toward the TCM now but just trying to make sure before i spend a few hundred

Tcm took a dump. My 11 threw same codes except po729. I replaced the Tcm all is well again after that.
 

duramaxzak

Wanna be puller!
Nov 22, 2008
2,431
14
38
Minnesota
I had my TCM go bad at about 60k miles and ended up destroying my transmission. Gm payed for the trans under warranty, but I had to pay for the new TCM.

I was told there's a problem with a internal ground that goes bad in the TCM.
 

rgullett83

Active member
Oct 27, 2008
1,607
0
36
Illinois
I replaced one last week in a 2011. U0101 set in the ECM and other modules as well

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Tothemax

xgmtech
Oct 16, 2014
607
8
18
new york
there not to bad around 350 iirc. the bad is it has to get towed to the dealer to be programed for around 1 hr labor. or there is a guy on ebay that sells new gm tcms already programed to your vin for I believe 400.
 

whytry

New member
Oct 11, 2010
282
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I would almost garrerntee it's the TCM ...I've had several with same symptoms as well...