97 k1500 5.7 4l60e shifting issues

[MountainManGarry]

Hey guys,
Hopefully someone can help me here, new to tuning. I have a 97 k1500 5.7 that has a 4l60e in it that was rebuilt maybe 10k ish miles before I bought the truck. when I first got it, the truck ran pretty poor. Engine was a crate motor 350 with 60k ish miles on it when I bought the truck (body has about 307k on it for anyone who cares). The owner said they put a very mild cam in the truck when they put that motor in and it ran good for quite some time before it acted up and they couldnt figure it out. The truck sat for 5ish years until I bought it. Got it running fairly decent with a new temp sensor and IAC but could never get it to run quite right, at this point the transmission worked perfectly. So after reading forums online for some time I decided to put a 0411 pcm in the truck and get rid of the black box. Since the 0411 pcm the transmission has not worked correctly at all. Itll jerk into gears, youve gotta let off the throttle almost the whole way just to get it to upshift most times, and there is absolutely no TCC lockup. Ive tried going down the road and commanding lockup and it says its 99% duty cycle but it will not lockup. I thought maybe somehow tow/haul mode is on but its not. At this point my only thought is that somehow the 4 wires that go to the transmisson from the pcm are not right. The wire colors are pretty faded so I tried looking up a connector end view on mitchell but I have found nothing. Maybe one of you have a picture of the connector with which pins are for switch signal a, b, c, and p. Ive gone off of Lextechs spreadsheet with wiring it up but unless any of you have any suggestions this is the only thing I can think of for why the trans wont shift right.

I have uploaded my tune file for anyone who wants to look at it incase something should be changed. I do have it tuned for my tires (35/12.5r18). Thanks in advance for anyone who can come through.

[blindsquirrel]

1997 K Pickup:
screenshot.10-09-2024 13.17.58.png screenshot.10-09-2024 13.18.11.png screenshot.10-09-2024 13.18.21.png

2002 Express:
screenshot.10-09-2024 13.24.19.png screenshot.10-09-2024 13.24.01.png screenshot.10-09-2024 13.24.10.png

[MountainManGarry]

Checked the wiring and I have everything wired in the correct spots. At this point I'm thinking it has something to the do with the tune.

[TransGo Robert]

The computer needs to do two things in order to get lock-up, it needs to first energized the TCC enable solenoid and then it needs to ramp up the PWM on-time % to reduce the slip. Yours is probably only doing the PWM solenoid part. Easy to tell, put a voltmeter on wire going to pin T of the transmission connector and see if the computer grounds it or not.

[dflintstud1]

did you use the drop down for trans option? l60/l80 cause that doesn't work, have to do a segment swap. get one from 02 vette with same OS level

add pids to your scan

look at what's available under Transmission.

shift and gear commanded will tell you shifts and gear in.. let you know if your prdnl is wired up correctly...

[MountainManGarry]

did you use the drop down for trans option? l60/l80 cause that doesn't work, have to do a segment swap. get one from 02 vette with same OS level

add pids to your scan

look at what's available under Transmission.

shift and gear commanded will tell you shifts and gear in.. let you know if your prdnl is wired up correctly...

Yea, the tune is selected on the drop down for the 4l60e. The wiring is correct, it shows me on the scan tool when I shift from park all the way down to 1 and vise versa. Going down the road it shows when the transmission shifts.

Used it last night and it shifts pretty decent when its cold but the longer you drive it, the worse it gets. The trans isn't overheating, Its around 130ish on the inlet and outlet of the trans cooler. The lines and whole radiator is brand new. Doesnt want to shift out of first unless your almost the whole way off the throttle which is impossible going up a hill. Then once your cruising and are in 3rd, barely give it any throttle and it downshifts for no reason at all. Reminds me why all my other vehicles are manual transmissions, aint gotta deal with issues like this.

[MountainManGarry]

The computer needs to do two things in order to get lock-up, it needs to first energized the TCC enable solenoid and then it needs to ramp up the PWM on-time % to reduce the slip. Yours is probably only doing the PWM solenoid part. Easy to tell, put a voltmeter on wire going to pin T of the transmission connector and see if the computer grounds it or not.

So I finally got the chance to bring the truck in the garage. Checked the tan/black wire from the round trans plug to the pcm and I got no continuity. Guess that figures out my TCC issue, not sure if that will fully fix the shifting of the truck but I guess I'll find out once I fix the wire.

[MountainManGarry]

Still no luck, so far I have went through and checked every wire that goes to the round transmission plug. I did find that the TCC solenoid wire was bad and ran a new wire to it. I checked and made sure I have plenty of trans fluid (its clean, changed it maybe 6-8 months ago). I decided to load a 2002 express van file to the pcm instead of the 2001 that was on it and had no change. At this point unless anyone has any other suggestions I think I'm going to try a new 0411 pcm since thats the only thing that changed since the trans worked flawlessly.

[TransGo Robert]

Still no luck, so far I have went through and checked every wire that goes to the round transmission plug. I did find that the TCC solenoid wire was bad and ran a new wire to it. I checked and made sure I have plenty of trans fluid (its clean, changed it maybe 6-8 months ago). I decided to load a 2002 express van file to the pcm instead of the 2001 that was on it and had no change. At this point unless anyone has any other suggestions I think I'm going to try a new 0411 pcm since thats the only thing that changed since the trans worked flawlessly.

Do you have full battery voltage on the tan/black wire at the computer end when you start the engine? If yes does it go down to zero when the computer commands lock-up or not?

[MountainManGarry]

Just checked and I have battery voltage when I start the truck but when I enable TCC nothing happens other than it goes down about .20v
I also checked TCC PWM Solenoid and when engine is on it has battery voltage, when I enable TCC it goes down to .75v if that helps at all

https://tinypic.host/images/2024/10/...001_160337.jpg
https://tinypic.host/images/2024/10/...001_160324.jpg

Wouldn't let me upload the pics for some reason.

[TransGo Robert]

Just checked and I have battery voltage when I start the truck but when I enable TCC nothing happens other than it goes down about .20v
I also checked TCC PWM Solenoid and when engine is on it has battery voltage, when I enable TCC it goes down to .75v if that helps at all

https://tinypic.host/images/2024/10/...001_160337.jpg
https://tinypic.host/images/2024/10/...001_160324.jpg

Wouldn't let me upload the pics for some reason.

OK so the circuitry is all good from the spot where you cheeked at the computer down to the transmission back up to the ignition switch. The driver in the computer is the one not doing its job or you have a bad connection between the wire terminal and the computer pin. If you were not back probing the terminal right into the connector, try that. If you still don't see a drop to zero or just about then check the fit of the female terminal on the computer pin before condemning the computer.

[MountainManGarry]

OK so the circuitry is all good from the spot where you cheeked at the computer down to the transmission back up to the ignition switch. The driver in the computer is the one not doing its job or you have a bad connection between the wire terminal and the computer pin. If you were not back probing the terminal right into the connector, try that. If you still don't see a drop to zero or just about then check the fit of the female terminal on the computer pin before condemning the computer.

Just checked pin fitment and no problem there. I've gotta call the computer on this one. I guess that's what you get for buying one off eBay, you never know what's wrong with it.

[TransGo Robert]

Just checked pin fitment and no problem there. I've gotta call the computer on this one. I guess that's what you get for buying one off eBay, you never know what's wrong with it.

As long as you were checking it before back probing the terminal directly in the computer connector and not piercing the wire then indeed that computer is defective. Very odd uncommon failure on this type of computer but there's always one here and there that does not follow the usual patterns of failure.

[MountainManGarry]

UPDATE: Got my new 0411 pcm today and installed into the truck. Took it around the block and it shifts like a brand new transmission again.

[TransGo Robert]

UPDATE: Got my new 0411 pcm today and installed into the truck. Took it around the block and it shifts like a brand new transmission again.

Great news, thanks for taking the time to post the fix.