Today's project was to get my 4L80 shifting correctly. This turned out to be somewhat of a learning experience and I never found all of this information in one place, so I thought I'd post what I've learned here.
I swapped a Gen IV 5.3 (LY5) into my '57 and, after the fact, decided to add a MP122 Magnacharger. I heard a lot of horror stories about the 4L60 transmission not being up to the task with the added power, so I decided to go with a 4L80. I found a 4L80 from a 2008 Express van with 10K miles for $800 and the swap was on.
The transition from Gen III to Gen IV engines (in the trucks) was in 2007. That's when they went from PCMs (Powertrain Control Module) to separate ECMs (Engine Control Module) and TCMs (Transmission Control Modules). I soon discovered that 2007 was also the year when the 4L80 started to be phased out in favor of the 6L80. As a matter of fact, the 4L80 was not offered at all in a Gen IV truck. It turns out that all factory Gen IV/4L80 combinations were 2008-2009 Express vans. After 2009, there were no 4L80s offered.
With a Gen IV, you can't necessarily change the OS in your ECM without turning it into an expensive doorstop. There are a lot of year to year changes that preclude this. Also, HP Tuners does not offer a segment swap for the transmissions in Gen IV applications. I'm not sure about EFI Live, so please reply to this thread if you have knowledge of how EFI Live works in this regard.
With all that background in mind, my first shot at making the 4l80 work was to just run it on a 4l60 tune. Lots of folks on the interweb are doing that with Gen III swaps, so it has to work, right? Wrong.
Here's the Reader's Digest version of that method for the Gen III folks, but it doesn't work for a Gen IV swap.
1) Wire in a relay to reverse the 2-3 shift solenoid control signal.
2) Wire in a relay to gate the TCC PWM (Torque Converter Clutch Pulse Width Modulation) control via the TCC control signal.
3) The 4l80 doesn't have a 3-2 solenoid, so you have to wire a 1K ohm 1/2 resistor to the control line.
4) Change the gear ratios in the tune to match the gears in the 4L80.
The steps above will take care of all the codes except P0717 which indicates that no signal is being sent by the ISS (Input Speed Sensor). This is a major gotcha for us Gen IV folks. The 4L60 has an ISS, but it puts out a square wave DC signal while the 4L80 ISS is essentially a VSS sensor and outputs an AC sine wave. HP Tuners can not disable code P0717 in a Gen IV ECM. I've heard that EFI live can disable the code, but that would still be an issue as it would cost more money just to get a DTC disabled by another tuner (because my tuner uses HP Tuners only).
In case anyone cares why the remaining P0717 code is important, it commands max transmission line pressure when it sets. This means your 1-2 shift will be in the first 10 feet of motion, the 3-4 shift will be really late, the torque converter never locks, and all the shifts are hard enough to rattle your teeth.
So, what's the fix? It turned out to be really easy (and inexpensive). Wire up your transmission like a 4L80 (i.e. no resistors or relays required). You can refer to the schematics for a 2008-2009 Express van, but, basically, you'll need to do the following:
1) At the transmission connector, remove the wires at pins "K" (orange), "S" (white), "T" (tan-black), "U"(brown), and "V"(Light Blue).
2) Take the brown wire (that used to go to pin "U") and put it in the transmission connector at pin "S".
3) We won't be using the wires that used to go to "S"(white) or "T"(tan-black). Just tie them up in the harness or strip them out if you prefer.
4) Take the wire that used to go to "K" (orange) and "V"(Light Blue) and run them to the external ISS on the 4L80. Of course, you'll need a connector from an old wiring harness or grab one at the junk yard. Pretty much all the VSS sensors use this 2-pin connector. It doesn't matter which wire is which on this two wire connection as it's an AC signal.
5) At the TCM connector remove the wires at pins "14"(White) and "25"(Tan-Black). This is the other end of the extra wires from step "3". Tie them up in the harness since they're disconnected at both ends or strip them out of the harness if you prefer.
6) Remove the wire at pin "45"(light blue) of the TCM connector and put it in pin "26".
7) You'll need a TCM from a 2008-2009 Express van (2500 or 3500). The hardware number is "24240449". The service number is "242423918290" Those numbers are right on the label on the TCM. I got one off eBay for $49 shipped because I was in a hurry. If you're willing to wait they're out there for $25. I just replaced my Silverado TCM with the Express van TCM. No programming required, just plug and play.
8) Enjoy your new 4L80! :tu
With the year-to-year changes of the Gen IV hardware and the lack of segment swaps available from the tuning software, it amazes me that the mismatched ECM/TCM combo works. But, thankfully, it does.
I hope this info helps someone who wants to use a 4l80 with their Gen IV engine.
I swapped a Gen IV 5.3 (LY5) into my '57 and, after the fact, decided to add a MP122 Magnacharger. I heard a lot of horror stories about the 4L60 transmission not being up to the task with the added power, so I decided to go with a 4L80. I found a 4L80 from a 2008 Express van with 10K miles for $800 and the swap was on.
The transition from Gen III to Gen IV engines (in the trucks) was in 2007. That's when they went from PCMs (Powertrain Control Module) to separate ECMs (Engine Control Module) and TCMs (Transmission Control Modules). I soon discovered that 2007 was also the year when the 4L80 started to be phased out in favor of the 6L80. As a matter of fact, the 4L80 was not offered at all in a Gen IV truck. It turns out that all factory Gen IV/4L80 combinations were 2008-2009 Express vans. After 2009, there were no 4L80s offered.
With a Gen IV, you can't necessarily change the OS in your ECM without turning it into an expensive doorstop. There are a lot of year to year changes that preclude this. Also, HP Tuners does not offer a segment swap for the transmissions in Gen IV applications. I'm not sure about EFI Live, so please reply to this thread if you have knowledge of how EFI Live works in this regard.
With all that background in mind, my first shot at making the 4l80 work was to just run it on a 4l60 tune. Lots of folks on the interweb are doing that with Gen III swaps, so it has to work, right? Wrong.
Here's the Reader's Digest version of that method for the Gen III folks, but it doesn't work for a Gen IV swap. 1) Wire in a relay to reverse the 2-3 shift solenoid control signal.
2) Wire in a relay to gate the TCC PWM (Torque Converter Clutch Pulse Width Modulation) control via the TCC control signal.
3) The 4l80 doesn't have a 3-2 solenoid, so you have to wire a 1K ohm 1/2 resistor to the control line.
4) Change the gear ratios in the tune to match the gears in the 4L80.
The steps above will take care of all the codes except P0717 which indicates that no signal is being sent by the ISS (Input Speed Sensor). This is a major gotcha for us Gen IV folks. The 4L60 has an ISS, but it puts out a square wave DC signal while the 4L80 ISS is essentially a VSS sensor and outputs an AC sine wave. HP Tuners can not disable code P0717 in a Gen IV ECM. I've heard that EFI live can disable the code, but that would still be an issue as it would cost more money just to get a DTC disabled by another tuner (because my tuner uses HP Tuners only).
In case anyone cares why the remaining P0717 code is important, it commands max transmission line pressure when it sets. This means your 1-2 shift will be in the first 10 feet of motion, the 3-4 shift will be really late, the torque converter never locks, and all the shifts are hard enough to rattle your teeth.
So, what's the fix? It turned out to be really easy (and inexpensive). Wire up your transmission like a 4L80 (i.e. no resistors or relays required). You can refer to the schematics for a 2008-2009 Express van, but, basically, you'll need to do the following:
1) At the transmission connector, remove the wires at pins "K" (orange), "S" (white), "T" (tan-black), "U"(brown), and "V"(Light Blue).
2) Take the brown wire (that used to go to pin "U") and put it in the transmission connector at pin "S".
3) We won't be using the wires that used to go to "S"(white) or "T"(tan-black). Just tie them up in the harness or strip them out if you prefer.
4) Take the wire that used to go to "K" (orange) and "V"(Light Blue) and run them to the external ISS on the 4L80. Of course, you'll need a connector from an old wiring harness or grab one at the junk yard. Pretty much all the VSS sensors use this 2-pin connector. It doesn't matter which wire is which on this two wire connection as it's an AC signal.
5) At the TCM connector remove the wires at pins "14"(White) and "25"(Tan-Black). This is the other end of the extra wires from step "3". Tie them up in the harness since they're disconnected at both ends or strip them out of the harness if you prefer.
6) Remove the wire at pin "45"(light blue) of the TCM connector and put it in pin "26".
7) You'll need a TCM from a 2008-2009 Express van (2500 or 3500). The hardware number is "24240449". The service number is "242423918290" Those numbers are right on the label on the TCM. I got one off eBay for $49 shipped because I was in a hurry. If you're willing to wait they're out there for $25. I just replaced my Silverado TCM with the Express van TCM. No programming required, just plug and play.
8) Enjoy your new 4L80! :tu
With the year-to-year changes of the Gen IV hardware and the lack of segment swaps available from the tuning software, it amazes me that the mismatched ECM/TCM combo works. But, thankfully, it does.
I hope this info helps someone who wants to use a 4l80 with their Gen IV engine.
