FastKat

iTrader: (10)

I have an LS1/4L80E in my project car. I used a friend's cable and PC to diagnose it using HPTuners. It looks like the 4L80E segment has all stock settings. The PCM recognizes the position of the gear selector (P, R, N, D, 3, 2, 1.) During a short test drive, HPTuners said the car is shift through the gears... 1st, 2nd, and 3rd. (We didn't go fast enough to hit OD.) However, I cannot feel any shifts at all. It seems like the car is starting in 2nd, and it certainly isn't shifting out of second, even on the highway going 60mph. I don't think the TCC is locking up either. The only DTC is an 0443, which is an EVAP solenoid.

The speedo is accurate. The VSS and PCM is reading the vehicle speed correctly.

I pulled the pan a while ago before running the car, and the fluid was nice and clean, etc. The fluid level is correct.

Any suggestions on what might be wrong? Maybe one or both actuators? Clutches?

Fbodyjunkie06

iTrader: (10)

Is the trans hooked to 12v?

IIRC when the 80e has 12v cut to it, it becomes engaged in "limp" mode which is 2nd gear and nothing else. Mine did this once when I cut the 12v feed wire with my shifter while test driving it after wiring some wires I hadn't wire loomed yet.

FastKat

iTrader: (10)

I think so but I haven't checked. The trans fuse is good and has power. I have not traced it down to the round connector though. That thing is a nightmare to get off - when I did my swap, I didn't leave much room there.

Reading up on the whole no power thing, it looks like my trans has all of the symptoms - but why am I not getting any codes?

slow67

iTrader: (2)

Are the codes enabled?

jimmyblue

iTrader: (11)

Can you see input shaft and output shaft RPM? This will
tell you the reality of gear selection (in/out ratio equals,
or does not, the indicated gear's mechanical ratio).

With a performance converter at WOT, you can fail to notice
a shift in higher gears because the converter just soaks up
the difference (shift extension).

FastKat

iTrader: (10)

I did the calculations, and at a 60mph highway cruise I am definitely not coming out of 2nd gear. The converter is a stock express van converter.

I'm going to log some data tomorrow. Input shaft/output shaft is on the list. I am also going to try to command the shift solenoids and TCC and see what happens.

If I manually shift my stock 4L80E converter into 1st gear, will it go into first, even if there are no electronics working?

FastKat

iTrader: (10)

Yea, I was browsing through the code list and saw transmission codes enabled. I specifically remember the shift solenoid codes.

DietCoke

iTrader: (18)

Trans in limp mode, or not getting power.

FastKat

iTrader: (10)

Okay, so... I pulled the round connector out of the trans and tested the wires coming from the PCM. The connector seems to be wired correctly. The power wire, which powers all of the solenoids, has a good strong +12v signal. When we use HP tuners to command gear changes, the solenoid wires ground (both ground for OD.) However, the solenoid ground wires have between 45-50 ohms of resistance when grounded by the PCM to initiate a solenoid - again, this is from the wires coming from the PCM, NOT from the solenoid.

Any suggestions? My next idea is to drop the pan and do the same test, but instead of testing at the round connector on the side of the trans, test the connectors inside the trans at the solenoid. That way, I'll be able to make sure it's not a bad connection inside the trans.

Any thoughts?

Also, how hard is it to change the solenoid wiring harness inside the transmission?

MikeyZ

iTrader: (20)

when you command the silinoid to turn on you can hear a pretty loud click if the engine is off.

FastKat

iTrader: (10)

We didn't do try that. Maybe I'll try that before I take the pan off. While the car was stopped w/engine off, we only tested off of the connector that comes from the PCM. It was unplugged from the trans. However, it really seems like nothing is happening when commanding shifts while the car is moving. No change at all in RPM, speed, etc - nothing at all.

However, while at a 50+mph cruise and after countless shift and TCC commands, the TCC finally did lock up two times, each for about one second. Converter slip went to zero. That is the absolute only solenoid activity we've gotten out of the car.

There is a single circuit that connects +12V power to all of the solenoids. I am thinking that something is wrong with that wire, and it is affecting all of the solenoids. I seriously doubt I have 3 solenoids that all went bad, or 3 solenoid connections that are all bad. Instead, I suspect the one power wire that is connected to all of the solenoids.

FastKat

iTrader: (10)

I took the pan off to change the internal wiring harness and both the 1-2 and 2-3 shift solenoids were broken. The pan was dented in from the bottom, and it came up and broke the solenoids. I probably did that when I was positioning the engine/trans with a floor jack.

I'm going to order some new solenoids and also install the internal harness. Hopefully that will work!

FastKat

iTrader: (10)

New solenoids in, car shifts great!