TBSS 4L60e to 4L80e T42 Swap

[Mike@Vengeance]

Okay Guys I have done a few F-Bodies with some help and never had a issue. I am trying to run a 4L80e from RPM Trans in a 2007 TBSS. Engine runs fine having difficulty getting the trans set up to work correctly. I have a issue it seems no matter what I try.

Here is the stock file from the Truck if anybody has tune I can seg swap or something they can help me with on this that woudl be great.

I am running the adapter Harness from Transcentral.com that should convert everything signal wise.

Thanks guys2007 TBSS T42 Reread.tun

[joecar]

What happens...?

[Mike@Vengeance]

I need a seg swap or something apparently to make it work. To my knowledge there are no E67 combined with a T42 (4L80e programs) If I full flash a E38/T42 (4L80e) program into the T42 it does shift but it is not correct.

The car has U1000 type code and the shif indicator light stays in 1st. The truck also shows NO SPEED on the log. I am using the TransCentral conversion harness that RPM recomended but according to RPM Trans they have never done a 4L80e swap on a TBSS in house so there informantion on this is limited at best.

The T42 program I posted is just a 4L60e T42 program that I tried to just swap the 4L80e stuff into but no luck with that.

I have looked and it can be done. I looked around and there is a HP guy that does it for like $1000 with a crossmember which I think is crazy.

Thanks for all your help

[joecar]

The 4L60E segment can run the 4L80E if the trans harness is modified...

basically:
- discard the 3-2 control solenoid signal,
- use a relay to invert the 2-3 shift solenoid signal,
- drive TCC PWM from TCC On/Off or from TCC PWM thru a relay gated by TCC On/Off;

( those changes a simple )

If you swap in a 4L80E segment you still have to modify the trans harness (TCC PWM pin has to be moved).

more info:

showthread.php?13090-4l80e-4th-gear-and-tcc-problem
showthread.php?13449-06-gmc-truck-os-swap
showthread.php?13722-Stop-TCC-unlock-when-coasting
showthread.php?13891-4L80-E-3-2-shift-solenoid
showthread.php?13644-4L80E-swap-into-2006-6.0L-truck-with-4L60E

[joecar]

So, it may be simpler to run the 4L60E segment (this being compatible with your E67).

[Mike@Vengeance]

The tune I posted is a Modified 4L60e program. I am running the adapter Harness form TransCentral but I guess that may not be right for what I am trying to do. I'll do some more reasearch from the post you made.

Anymore ideas please let me know.

Thanks for all your help

[joecar]

The 4L60E segment can drive the 4L80E only if those modifications are made to the wire harness.

[turbo_bu]

Sort of a similar question to the OP about this kind of swap:

I know that for the LS1B family of PCM's, there is an issue with the 4L80E's unlocking the torque converter clutch when you take your foot off the gas. One of the fixes is to use the 4L60E OS and simply rewire the pins connecting the PCM to the transmission (along with a relay due to polarity on one of the solenoids). Thus you are really still using a 4L60 OS PCM to control the 4L80.

For vehicles that use the ECM / TCM combinations, the TCM (T42) is inside the transmission. My question is can you simply "rewire" a 4L60E T42 to control a 4L80E? I have not had one of these newer transmission apart to see how much space there is to work, but am curious to know if this is even possible ... Or if there is enough room to fit in the needed relay too.

Or, did GM "fix" the 4L80E issue so that is no longer unlocks the TCC when you take your foot off the gas?

[joecar]

The T42 is external to the transmission (it controls the 4L60E/65E/70E and the 4L80E/85E).


Anything other than the F-car and Y-car unlocks the TCC (for both the 4L60E/65E/70E and the 4L80E/85E).

[N0DIH]

I never looked at that on my 4L80E in my Suburban (99 K2500 454). Will check on that. I know my 94 Fleetwood LT1 with the RPO V4P (7000 lb tow package) has some different options checked for thie 4L60E (HD version, has lots of special stuff in it factory, I suspect most shift kits are based on this trans). And you can check on/off the TCC to unlock/lock on decel. I could force DFCO down to 800 rpm or so and having that option was key)