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will the wiring harness from a 4L60 lt1 fit a T56 lt1

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Old 07-23-2010, 09:27 PM
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Car: 89RS-5.0/88IROC-Z-5.0/92-5.7 z28/v6
Engine: 5.0/5.7/2.8
Transmission: 5 spd in two stock auto in other tw
Axle/Gears: stock
will the wiring harness from a 4L60 lt1 fit a T56 lt1

im trying to buy the right donor car but this one is auto and i need manual t56 i just need to know if the wiring harness from the auto will fit a new t56 tranny or i f i will need all new setups for this and if i do what do i need to swap the 4L60 off and a t56 on the lt1
Old 07-23-2010, 09:42 PM
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Car: 88 Iroc
Engine: 94 lt1 modded
Transmission: t 56
Re: will the wiring harness from a 4L60 lt1 fit a T56 lt1

An auto harness can be made to work fairly easily. I have an auto harness in mine. I finally removed the auto plug a couple of years ago, I ran it mostly stock for quite a while though. you might need to lengthen the speed sensor wire, I don't remember. also you should get the pcm reflashed with a manual file so you don't get a treans inop check fault code.
Hope this helps.
Kory
Old 07-24-2010, 07:16 PM
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Car: 92 Firebird
Engine: Supercharged 6.0
Transmission: T56
Axle/Gears: 8.8 3.73
Re: will the wiring harness from a 4L60 lt1 fit a T56 lt1



Its not very difficult. Remove the 13-14 wires associated with the 4L60E connector (4 wires for 93 4L60's) and run one wire from the PCM to drive the reverse lock solenoid. Use the old IGN wire from the 4L60E (youll have to run a new IGN wire for 4L60's)

VSS wires stay the same, but the pulse count changes. A tune is required to get the speedo accurate again and to disable the auto trans stuff

Hopefully you're doing this on a 94+ harness. The 93's arent good for much
Old 07-24-2010, 07:29 PM
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Car: 89RS-5.0/88IROC-Z-5.0/92-5.7 z28/v6
Engine: 5.0/5.7/2.8
Transmission: 5 spd in two stock auto in other tw
Axle/Gears: stock
Re: will the wiring harness from a 4L60 lt1 fit a T56 lt1

the harness is coming from a 93 4l60
should i plan to do this my self i have had no expierence?
Old 07-24-2010, 08:57 PM
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Re: will the wiring harness from a 4L60 lt1 fit a T56 lt1

Read this

https://www.thirdgen.org/forums/ltx-...rt-finish.html
Old 07-24-2010, 09:27 PM
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Car: 89RS-5.0/88IROC-Z-5.0/92-5.7 z28/v6
Engine: 5.0/5.7/2.8
Transmission: 5 spd in two stock auto in other tw
Axle/Gears: stock
Re: will the wiring harness from a 4L60 lt1 fit a T56 lt1

that looks confusing

Last edited by five7kid; 07-24-2010 at 10:47 PM. Reason: Language
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