06 GTO M6 to 4L80e

[kjhallex]

Well the time has come to get rid of the six speed. I plan on getting a optishift controller (any suggestions on it?) I want to know if I need to keep the manual tune or change it to an auto? I would think I can keep a manual tune if I have a standalone controller. Another option is to get a auto trans engine harness and TCM and go that route since they make adapters to go from 4l60 to 4l80 now. I just think the standalone might be easier and less work.

Any advice is appreciated!

[Ben Charles]

No need to get a controller, use the GM stuff.

[kjhallex]

No need to get a controller, use the GM stuff.

Now you have me thinking. That would make things easier though, just is going to be a pita to change the harness out.

[GNXClone]

I switched from an M6 to a 4L80e in my '06. Actually, I switched to the 4L65e first, about three of them, then the 4L80e.

It's not that difficult if you get the A4 harness and TCM.

In short, controller-wise, swap out the engine harness, add the TCM, reprogram the ECM and TCM with the A4 OS using HP Tuners. Use a Tech-II to reprogram the PIM and IP to A4.

Done!

You'll retain cruise control, speedometer, torque management (if you want it), etc. And you'll be able to tune (and log!) both your engine and trans with HPT.

Aftermarket controllers are costly, do not retain features like cruise control, and are likely more difficult to install than an OEM harness.

You can build an adapter to run the 4L80e from the 4L65e control program for less than $20 in Radio Shack parts (two relays, two resistors) and a couple hours of your time. And the only transmission DTC you'll need to disable is P1870, which HPT does give you access to.

[GNXClone]

Oh, it's MUCH more of a PITA to swap out the pedals than it is the harness. Trust me!

You'll also need a custom drive shaft and trans mount. The harness will be the easy part.

[kjhallex]

Thanks GNX! I've been following your build on ls1gto. And it seems you have everything figured out now. I'm in the process of tracking down a TCM and harness now lol. I keep hearing how bad the pedals are so I'm not looking forward to that part lol. I have a local place here that will make me a drive shaft for around $500 if it's more I will just order one from DSS or gforce.

[kjhallex]

I switched from an M6 to a 4L80e in my '06. Actually, I switched to the 4L65e first, about three of them, then the 4L80e.

It's not that difficult if you get the A4 harness and TCM.

In short, controller-wise, swap out the engine harness, add the TCM, reprogram the ECM and TCM with the A4 OS using HP Tuners. Use a Tech-II to reprogram the PIM and IP to A4.

Done!

You'll retain cruise control, speedometer, torque management (if you want it), etc. And you'll be able to tune (and log!) both your engine and trans with HPT.

Aftermarket controllers are costly, do not retain features like cruise control, and are likely more difficult to install than an OEM harness.

You can build an adapter to run the 4L80e from the 4L65e control program for less than $20 in Radio Shack parts (two relays, two resistors) and a couple hours of your time. And the only transmission DTC you'll need to disable is P1870, which HPT does give you access to.

Ok, I have a couple of questions now. Did you get a new tcm and program it with hp tuners or was it out of another gto? I thought they had to be VIN matched? Also how did you go about changing your OS from manual to auto? After I do that the car will start and drive without a tech 2 correct? The tech II is just to get the cluster to read what gear your in?

Thanks for your help, and post up some videos on LS1gto of you car IF you can keep it straight lol.

[cjwhite28]

I am building a street rod with an an turbo 5.3 l33 with 06 tbss intake e40 computer and wiring. I am also wondering like kjhallex has asked. if i want to go from 4l70 to 4l60 or 4l80. what is the step by step.

I understand i need a different TCM for the transmission. But do i need to get a tech 2 and match the tcm to the ecm?

The more detail the better

Thanks in advance

[GNXClone]

I can only comment on the 05/06 GTO setup as that is what I am familiar with.

The TCM is the same for 4l60 and 4l80, it's a T42. In my case, I am using the 4l60 program to control the 4l80. This requires adding two relays and two resistors. One relay to reverse the Shift-B solenoid polarity and another relay if you want to keep PWM controlled TCC lockup (versus on/off lockup which IMO can be harsh). The resistors fake the T42 into reading the presence of of the 3-2 shift solenoid and TCC PWM solenoid (when the enable relay is in the off position). The resistors keep the T42 from throwing codes and going into limp mode which in-turn keeps the trans in 3rd gear.

You can also program the T42 with a 4L80 control program from a 2007/2008 van or truck. This requires moving a few wires in the harness. I was going to use this method, but decided against it because most everyone complains about how the truck program unlocks the converter at 0% TPS. Also, programming the TCM with a different control program than the ECM expects could be tricky with HPT. Using the existing 4l60 control program keeps it simple.

I've had no issues with the VIN in the TCM. It seems the vehicle doesn't care about the TCM's VIN.

kjhallex: The car will start, and move. I moved my car out of and back into the garage with the TCM completely disconnected. The TCM may not be able to communicate with the ECM without first programming the PIM. But I'm really not sure about this as I programmed mine right away. If the TCM cannot communicate, the trans will still go into gear (2nd I think, and reverse), but it will not shift.

[kjhallex]

Thanks GNX! I sent you a pm on the other site.