Help! No transmission indicator, No Manual gears after transmission swap.

[Nawa]

I just swapped my transmission in a 5.3L 2009 Chevy Tahoe which is a 6 speed, with a used 6.2L 2007 Gmc yukon 6 speed transmission, now I don't get the gear shift indicator on the instrument cluster, and not showing manual transmission gears when I shift into manual, I was wondering if I get the old TCM attached to the harness and Read the tcm file through Hp Tunners, then I write back the file into the new transmission control unit, is it going to work or I need online programming?
No dtc on both tcm and ecm, Plus I can't reset adaptations through the scan tool it gives errors.
I will be thankful for any help I can provide video as well

 

[donjetman]

@NickTransmissions

 

[NickTransmissions]

I just swapped my transmission in a 5.3L 2009 Chevy Tahoe which is a 6 speed, with a used 6.2L 2007 Gmc yukon 6 speed transmission, now I don't get the gear shift indicator on the instrument cluster, and not showing manual transmission gears when I shift into manual, I was wondering if I get the old TCM attached to the harness and Read the tcm file through Hp Tunners, then I write back the file into the new transmission control unit, is it going to work or I need online programming?
No dtc on both tcm and ecm, Plus I can't reset adaptations through the scan tool it gives errors.
I will be thankful for any help I can provide video as well

Either swap your VB-TEHCM-IMS/Harness/SS assembly from your 2009 to the 2007 unit or program the 2007 unit's TEHCM to work with your 2009 Tahoe. These units are not just 'swap-and-go' like the four speed autos (4L60E, 4L80E). Also why not just have your 2007 rebuilt or rebuild it yourself? Used 6L80s are somewhat of a gamble, given all their problems...

Lastly, did you buy a new torque converter with an upgraded converter clutch?

 

[Nawa]

Either swap your VB-TEHCM-IMS/Harness/SS assembly from your 2009 to the 2007 unit or program the 2007 unit's TEHCM to work with your 2009 Tahoe. These units are not just 'swap-and-go' like the four speed autos (4L60E, 4L80E). Also why not just have your 2007 rebuilt or rebuild it yourself? Used 6L80s are somewhat of a gamble, given all their problems...

Lastly, did you buy a new torque converter with an upgraded converter clutch?

Thanks for your reply, I see a misunderstanding my car is 2009 chevy tahoe, and the new used transmission is from a 2007 yukon, they both have the TCM inside the transmission and has both manual and automatic drive, not from 1 till 3 then D' Drive which is a 6 speed but not sure which model, plus I need directions for programming can I use Hp Tunners to do the reflashes I mentioned above? About torque converter, no I used the one that already came with the yukon's transmission around my area it's a little hard to get hands on upgraded torque converters

 

[Doubeleive]

one would presume since you are unable to perform the re-learn (required) and it just gives you communication errors and a lack of display on the cluster
that you might have a bad connection somewhere, perhaps the harness is not fully seated or a pin is pushed out, etc. hopefully externally.
that's my best guess I would recommend "double checking" your work.
**also check your fuses if you performed any work with the battery still connected, or just to rule it out regardless.

 

[NickTransmissions]

Thanks for your reply, I see a misunderstanding my car is 2009 chevy tahoe, and the new used transmission is from a 2007 yukon, they both have the TCM inside the transmission and has both manual and automatic drive, not from 1 till 3 then D' Drive which is a 6 speed but not sure which model, plus I need directions for programming can I use Hp Tunners to do the reflashes I mentioned above? About torque converter, no I used the one that already came with the yukon's transmission around my area it's a little hard to get hands on upgraded torque converters

No misunderstanding my part but maybe on yours.

What I'm telling you to do is remove the TEHCM/VB/SS/IMS assembly (six inverted torx E12 bolts plus the case connector gate latch lifted and it comes off the transmission) from your Tahoe's origional 2009 6L80 and install it into the 2007 replacement transmission. Then fill it back up with fluid, fire it up and see what happens...The 2009 TEHCM which came from your original transmission, is programmed to your vehicle, the 2007 is NOT (unless you have already programmed it which doesn't seem to the case). Also check the case connector plug to see if it's fully plugged in as suggested above - who knows, it may be as simple a fix as that...

Also, why is it hard to get your hands on an upgraded torque converter in your area?
FTC would drop ship an upgraded TC to your door. Their website can be found by clicking here. Plan on doing r/r again and if that converter fails in the ways they usually do, you'll be rebuilding that 2007 transmission...Don't get rid of your 2009 original unit.

Here's what I'd do: Take your original 2009 6L80 into a local reputable transmission shop and have them go through it soup-to-nuts...Check out my 6L80 Information thread for details on what parts should be replaced, procedures performed and updates installed (link is in my signature line) so you can ask the shops you speak to about how they rebuild these units and compare to my list. You can see what they may give you for the 2007 unit as a core or to have in the event the 2009 needs hard parts.

I really don't know why folks gamble on these transmissions buying them used since they have so many problems that can put you on the side of the road...In my professional opinion, they are not much better bets when bought used units than 4L60Es. The torque converters, pumps, valve bodies, TEHCMs and, for early units like the 2007 you bought, 3-5-R drum leakage and 1-2-3-4 piston cracking are the most common pattern failures that occur with the 6L80/90s. The 90s are a bit more reliable but not hugely since they largely suffer from the same problems.

Hopefully you paid no more than $500 for the used 2007 transmission.

 

[Nawa]

No misunderstanding my part but maybe on yours.

What I'm telling you to do is remove the TEHCM/VB/SS/IMS assembly (six inverted torx E12 bolts plus the case connector gate latch lifted and it comes off the transmission) from your Tahoe's origional 2009 6L80 and install it into the 2007 replacement transmission. Then fill it back up with fluid, fire it up and see what happens...The 2009 TEHCM which came from your original transmission, is programmed to your vehicle, the 2007 is NOT (unless you have already programmed it which doesn't seem to the case). Also check the case connector plug to see if it's fully plugged in as suggested above - who knows, it may be as simple a fix as that...

Also, why is it hard to get your hands on an upgraded torque converter in your area?
FTC would drop ship an upgraded TC to your door. Their website can be found by clicking here. Plan on doing r/r again and if that converter fails in the ways they usually do, you'll be rebuilding that 2007 transmission...Don't get rid of your 2009 original unit.

Here's what I'd do: Take your original 2009 6L80 into a local reputable transmission shop and have them go through it soup-to-nuts...Check out my 6L80 Information thread for details on what parts should be replaced, procedures performed and updates installed (link is in my signature line) so you can ask the shops you speak to about how they rebuild these units and compare to my list. You can see what they may give you for the 2007 unit as a core or to have in the event the 2009 needs hard parts.

I really don't know why folks gamble on these transmissions buying them used since they have so many problems that can put you on the side of the road...In my professional opinion, they are not much better bets when bought used units than 4L60Es. The torque converters, pumps, valve bodies, TEHCMs and, for early units like the 2007 you bought, 3-5-R drum leakage and 1-2-3-4 piston cracking are the most common pattern failures that occur with the 6L80/90s. The 90s are a bit more reliable but not hugely since they largely suffer from the same problems.

Hopefully you paid no more than $500 for the used 2007 transmission.

Understood brother, I am from Iraq and I do my repairs ordering items would take months to arrive I paid like $1200 for the transmission with guarantee, a new torque converter costs like $750 rebuild costs around $400, it's close to the used transmission itself and parts here are not upgraded for the rebuilding so why not a new transmission the system here is different, I will try to get the old TCM / valve body back to the new tranny and see what happens thanks for advices.