1995 4L80E vs 1998 4L80E ~ Using a '427 PMC $OE/$31

[dave w]

I'm wondering if a '427 PCM (1995 $OE/$31) can operate the electronics for a 1998 4L80E?

Some information I found on the "net" 1994 and up have the same connectors and the 614 Hz Force Motor.

dave w

[pmkls1]

AFAIK there aren't any differences in any of the 4L80E electronics from '94-up and technically any controller capable of operating a 4L60E series with pwm tcc controls should be able to operate a 4L80E and vise versa. There weren't many changes the 4L80E at all over the years really. Unlike the 4L60 lines, the 4L80 never changed bell housing depth and the flywheels and torque converters were the only differences between 4L80s mounted to LS engines and those mounted to big blocks and Gen 1 small blocks IIRC. I know it's not "solid" proof, but it is perhaps more evidence supporting what you have found thus far.

[RobertISaar]

the only significant control differences between a 4L60 and 4L80 is that the:

4L60 had the TCC + TCC PWM solenoid compared to the 4L80 TCC PWM
4L80 had an input speed sensor, 4L60 did not
4L60 had the 3-2 downshift solenoid, 4L80 did not

everything else is minor and can be accounted for in the calibration.

also, i don't see any reason why you couldn't control the newer trans with the older PCM... FMC/PCS frequency shouldn't be THAT sensitive unless you got down to some really low frequencies. the 64Hz that a P4/P6 can control should be plenty. the TCC PWM on a lot of somewhat recent stuff was still pulsed at 32Hz.

[one92rs]

not sure if this is relevant. but in my 2002 chevy silvy I was building I put a 1997 4l80e in it. I went with the 97 due to both cooling fittings being in front instead of the tube running inside. all I did was a copy a 2002 2500 truck table in my pcm and it worked fine. if it worked in my 02 I don't thing a darn thing is different.

[one92rs]

found this.

[pmkls1]

Yeah, like I said there weren't many changes made overall and was also fairly sure that most controllers were capable of operating either/or. The 4L60 vs. 4L80 stuff is irrelevant to his question though. I still have never seen or heard of any differences in the electronics of the "later" 4L80s though. Never messed with the early units, just the 93/94-later models.

[comerz1]

Good info here. I am working on a project with a 4l80e, pretty sure it's out of a 99 but not positive. Motor will end up being TBI with a 7427 ecm, which I don't have yet. Also need the wiring harness. So are the harnesses the same regardless of transmission? Did they put 4l80e in 2wd in 94-95? If no 80's in 2wd, will there be extra plugs that went to the transfer? Just need a direction on where to start looking for a wiring harness. Hopefully I can find a donor that has all of the TBI setup, harness, pcm, etc. but I may have to piece it together.