Vortec 454/4L80e HD swapped 1999 Tahoe OBS

[bigfootchiro]

https://sites.google.com/site/sloppywiki/everything-ls/4l80e-info


never done it, but seems pretty straight forward. i would recheck the wiring tbh

Thank you. That's my next step with that plug. Looking back from day 1 of the swap, I remember my buddy saying it started off very slowly once in gear (probably in limp mode), then months later my TC started unlocking and locking randomly, then stopped working altogether. After that, I started having the issue of coming to a stop and it starting in 4th, then dropping to first (probably going in and out of limp mode). Now it's probably completely shorted and blowing the fuse. All of these issues seem to lead to that ONE pink wire!

 

[bigfootchiro]

FIXED IT!!! Somehow the 12V pink wire and Range Signal A pink wire were crossed and connected incorrectly. 12V going to Range A and vice versa. Not sure how that was even possible, since it drove fine for a long time.

Tomorrow afternoon, I'm going to retap the new 4 pin NSS plug and install it, then it's off for a drive!

 

[Sam Harris]

FIXED IT!!! Somehow the 12V pink wire and Range Signal A pink wire were crossed and connected incorrectly. 12V going to Range A and vice versa. Not sure how that was even possible, since it drove fine for a long time.

Tomorrow afternoon, I'm going to retap the new 4 pin NSS plug and install it, then it's off for a drive!

Nice! Excellent news!

 

[bigfootchiro]

Installed the new plug and retapped the wires. Still throwing the P0706 code, and even when cleared, still can't do the crank relearn procedure. Tried with a Launch scanner and a Snap On. We figured out the "AC relay ON" issue, and got past that. Supposedly, you have to manually input a 2001 Express Van 5.7 into the scanner to do the procedure properly. Got to the WOT til fuel cutoff is supposed to occur (which is supposed to be 4500 rpm), and it goes straight to the rev limiter. PCM won't complete the procedure. Now I'm having to send the 0411PCM back to the guy that made it and have him send me a new one with the NSS tuned out.

 

[bigfootchiro]

Alright guys, I come to you for your superior knowledge once more!

I hooked up the new 0411PCM and was having a high idle issue just like the last pcm. Somehow, it finally settled down and I did the crank relearn. FINALLY TOOK!!! No more issue there.

However, I'm using a Snap On Solus Ultra, changed the vehicle information so I could read for a 4l80e, and looked at the data... ISS reading is close to RPM value, TCC reads around -60 in P/R, 500-600 in gear. Transmission is starting off in 2nd gear, per the Solus, and I even caught it reading 2nd for a moment when I shifted into Reverse. Solus reads a 1-2 shift time of 0.03 seconds, as soon as I put it in gear. If I let off the throttle when taking off, it will stall and die. It will do that at times when I hit Reverse. Sometimes I shift directly to Reverse or Drive and it stalls immediately.

Took it out of the driveway for a drive around the block to see if it will shift gears. It is erratic, and shifts into 3rd way too quickly. Not holding gears at all, and starts in 2nd. I checked the voltage to the transmission, and I'm getting 12V.

Trying to think if any other information to give you guys. I still have the Solus, so if you guys need any other information, I can get it for you.

Also have a leak at the tail housing adapter as it connects to the transfer case. Leaks pretty significantly. A drop every 10-20 seconds or so. I wouldn't think this would cause a significant enough drop in line pressure, but maybe I'm wrong? Transmission temp only reads around 120-130

 

[randeez]

are you using the front vss or the rear?
cause the front will always be close to the rpm-converter slip

you need to be using the rear sensor, make sure the gear ratios are correct in the tune, and there is something with the solenoids that may need to be changed/adjusted. can be done hardwire or in the tune iirc.
but its like theres 2 shift solenoids for 4 gears, which gear is selected depends on position of both solenions 1on/2off , 1on/2on, 1off/2on and its different between the 4l60 and the 4l80

 

[bigfootchiro]

are you using the front vss or the rear?
cause the front will always be close to the rpm-converter slip

you need to be using the rear sensor, make sure the gear ratios are correct in the tune, and there is something with the solenoids that may need to be changed/adjusted. can be done hardwire or in the tune iirc.
but its like theres 2 shift solenoids for 4 gears, which gear is selected depends on position of both solenions 1on/2off , 1on/2on, 1off/2on and its different between the 4l60 and the 4l80

It's funny you say this, because right after I posted I checked the solenoids, and when you command the 1-2 ON, it turns ON, but when you control the 2-3 ON, it turns OFF. Don't think that's supposed to happen. The tune in the PCM should be correct, because it was tested on an 0411PCM swapped 454/4L80e before I put it in.

Tool it back to the transmission guy after I told him the results and he's supposed to have it done by Monday. Switching out the valve body, solenoids, and internal wiring harness.

 

[bigfootchiro]

Here we go! Finally got down to the nitty-gritty, supposedly. The 2-3 shift solenoid and internal harness were faulty somehow, and the transfer case was stuck in 4Lo, which explains the "dragging" sensation. They were doing hole shots in the parking lot with it yesterday, so today I pick it up! Hopefully it works right this time lol. If it does, next up is exhaust!

 

[Tonyrodz]

Here we go! Finally got down to the nitty-gritty, supposedly. The 2-3 shift solenoid and internal harness were faulty somehow, and the transfer case was stuck in 4Lo, which explains the "dragging" sensation. They were doing hole shots in the parking lot with it yesterday, so today I pick it up! Hopefully it works right this time lol. If it does, next up is exhaust!

That sounds encouraging.

 

[bigfootchiro]

That sounds encouraging.

Well it did, then I drove it home. Shifts weren't right, and felt like it was bogging. Come to find out the output sensor was wired to rear of transmission and not transfer case, causing shifts to act quickly. Rewired and it was better, but felt like it was still hunting gears unless under WOT. Thay may be fixed with tuning.

Go driving down 275 for about 20-25 minutes and it's not acting right. Hook up scanner and trans temps are at 280. Found out the guy never installed the aftermarket TruCool 40K cooler, so ordered that and waiting for it to come Tuesday.

I'm hoping the cooler will fix most of the cooling issue so I can purchase and hookup HPTuners to tune the shift points. Hoping that's all it needs, or I'm at a loss lol

Anything else I should be looking for that could be causing cooling issues?