97 2500 Chevy

[dj_97]

Ok, I see.

I did a NBS 1500 4L80e swap, but I don't know how that differs on the OBS. I seem to recall the OBS has 2 connectors per side, but later they lumped 2 connectors together. I'm talking on the ECU side. You'll need a ECU pin out for your truck. A guy name @Lextech here used to get them...but sure if he's still active.

On the transmission connector you can see my thread on the LS + Carb Swaps and hopefully it's the same for you year. I'm guessing it is because the electronics of those tranmissions we're all the same. But double check first.

Good luck.

Bare with me, what the hell is a pin out? Lol sorry if I seem foolish, never heard of it before. Like I said, I’m used to old TBI or carbs and not much on electrical

 

[stutaeng]

Bare with me, what the hell is a pin out? Lol sorry if I seem foolish, never heard of it before. Like I said, I’m used to old TBI or carbs and not much on electrical

It's the arrangement of the wires on the connector.

On post #7 & #8 I did my best to cover it.

'99 Silverado 4.3 to 5.3 Swap with 4L80e bonus

Hello, finally starting on my 99 Silverado ECSB 1500 2wd 4.3/4L60e/3.42 NBS. I've had it since my college years and has been pretty reliable, but has had very low oil pressure and the tranny is acting up. No money for a engine/tranny rebuild, but would like to put some life back into it. Finally...

www.gmt400.com

Another option is to get a conversion adapter. Amazon has them for like $95. You literally plug your stock connector on one end and to the 4L80e at the other end...but you still have to buy the output speed sensor and connect it back to the ECU. The 4L60e has one speed sensor, while the 4L80e has 2, so you have to add the second one.

If you do it the way I showed, you'll only need the speed sensor with a short pigtail. It's around $15. The stock wiring gets modified, so there's no additional expense there. Otherwise just get the adapter.

I hope this helps.

 

[stutaeng]

Actually, that adapter is cheaper here, and comes with that long speed sensor.

So all you have to do is figure out
where to plug that speed sensor and get your ECU reflashed.

Make sure you give them the correct gear ratio so your speedometer and the transmission shift points are correct.

Transmission Plug and Play Adapter Harness Connector Fit for 4L60E to 4L80E LS Swap Silverado Sierra Trans, Wire Adapter Harness Kit Compatible with 1998-2006 Transmission

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[dj_97]

Actually, that adapter is cheaper here, and comes with that long speed sensor.

So all you have to do is figure out
where to plug that speed sensor and get your ECU reflashed.

Make sure you give them the correct gear ratio so your speedometer and the transmission shift points are correct.

Transmission Plug and Play Adapter Harness Connector Fit for 4L60E to 4L80E LS Swap Silverado Sierra Trans, Wire Adapter Harness Kit Compatible with 1998-2006 Transmission

xc_hide_links_from_guests_guests_error_hide_media

Thanks man. Hopefully I’ll get the motor and harness from the 96 to the 97 soon and I can figure all this out

 

[dj_97]

Actually, that adapter is cheaper here, and comes with that long speed sensor.

So all you have to do is figure out
where to plug that speed sensor and get your ECU reflashed.

Make sure you give them the correct gear ratio so your speedometer and the transmission shift points are correct.

Transmission Plug and Play Adapter Harness Connector Fit for 4L60E to 4L80E LS Swap Silverado Sierra Trans, Wire Adapter Harness Kit Compatible with 1998-2006 Transmission

xc_hide_links_from_guests_guests_error_hide_media

I actually think that’s the wrong connection, this is a 1996 harness from the Yukon going into the 1997

 

[dj_97]

This is the 96 connectors, I’ll try for better pics tomorrow. But the 97 looks to have the same or similar connections

 

[dj_97]

Actually, that adapter is cheaper here, and comes with that long speed sensor.

So all you have to do is figure out
where to plug that speed sensor and get your ECU reflashed.

Make sure you give them the correct gear ratio so your speedometer and the transmission shift points are correct.

Transmission Plug and Play Adapter Harness Connector Fit for 4L60E to 4L80E LS Swap Silverado Sierra Trans, Wire Adapter Harness Kit Compatible with 1998-2006 Transmission

xc_hide_links_from_guests_guests_error_hide_media

Okay. So I pulled a wiring diagram out on both the 96, and the 97. The only difference I’m finding thus far is this, the 96 has a TCC solenoid the 97 doesnt, and the 96 has a 3-2 CTRL solenoid. Everything else is the same, runs to the same pins same wires codes etc. so I need to just unpin the 3-2 and TCC solenoid from the 96 harness? That’s what I’m gathering from it at this moment. Also, the 97 has a input shaft speed sensor, the 96 does not. I think I’m gonna just go for it, see what problems arise, and proceed from there. I may have found a localish junk yard that would have a harness for the truck (possibly)

 

[stutaeng]

I don't remember exactly what those wires affect back at the ECU. All the sources that I read show the same information, so it's probably the same thing you are finding.

FYI: On your truck, the rear speed sensor is most likely on the transfer case. On the 4x4 transmissions, the rear speed sensor have a "dummy" sensor. The reluctor inside the transmission is often omitted, since the data is collected from the transfer case.

 

[dj_97]

You must be registered for see images attach

okay guys. I found this replacement harness but I’m curious now. This would fit my Yukon or 3/4 ton, so that has me guessing the Yukon harness will fit the 3/4 ton? I really don’t wanna buy a harness unless I have to honestly lol. This says it work with 4l60 or 4l80… I’m just spit balling right now. I have the harness from the Yukon loose and on top of the engine ready to pull. Gonna finish pulling the 3/4 harness out tomorrow then I’ll compare?

 

[dj_97]

@thegawd i finally found you lol