ls swap transmission shifting problem whats going on

[Bulldog88]

Im working on a truck that has a 4l60 but will not shift properly , I had the transmission looked at and changed the solenoid out, and still dont have first gear or second what could be happening, the transwas checked out by a professional trans builder can someone help me out did I do something wrong during the swap
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[68GMCCustom]

was your trans originally with your motor and ecm....or did it come from a different vehicle?

[Bulldog88]

Yes everything came from the same truck motor, trans, ecm, and harness, is it possible that the throttle position sensor is no good and not telling the computer when to make the trans shift
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[68GMCCustom]

do you have a DTC light indicating a fault? is there a DTC code?

[BR3W CITY]

How do you know that you only have third? Are you looking at what gear the computer thinks its in, or can you mechanically feel it not going into 1 or 2.

Do you have reverse?

[Bulldog88]

It was throwing out the solenoid code but it not doing that anymore, I did it two different ways I jacked the truck up and manual shift it, then I put it and drive and let it do it on its own and it does nothing, the third time I drove it around the block and it has no power at all it feel like it takes off in maybe third gear
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[clinebarger]

The PCM has codes in it....
Does the trans have ignition voltage at the big round plug??

A 4L60E will "default" to 3rd gear only if power is lost to the shift solenoids.

[BR3W CITY]

I think Pin E is the one in question, iirc its a red wire can be loose/cut/broken, or just doesn't have power going to it.

Is the VSS plugged in and wired correctly?

And for the third time; what codes is/was it throwing? They will still be readable in the computer even if the light turned off. You could have a non-transmission related mechanical/electrical problem thats putting it into limp mode.

[Bulldog88]

I have ignition voltage, at the plug on the red wire, the scanner was throwing codes solenoid 1 and 2 but thats been replaced and no longer have any codes, but still nothing

[68 short step]

sounds like you are trying to run a 4l80e tune on your 4l60e trans.. or the wiring to the trans/ecm is for a 4l80e....on your trans connector, round plug at trans, does it have a pin in the 'T' and 'U' spots on the connector?

[Bulldog88]

Yes theres a tan wire with black stripe on the t spot and a brown wire in the u
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[Bulldog88]

Yes theres a tan wire with black stripe on the t spot and a brown wire in the u
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[Bulldog88]

Ok so I pulled the transmission back out got it rechecked everything is good, has anyone ever heard of someone installing a faulty program into your Ecm, or a tune that is not good that causes problems

[Bulldog88]

I hooked up the scanner to the obd2 and the scanner is telling me there is no communication, Im using a snap on scanner

[eagleuh1]

If your using the stock harness, at least for my 2005 5.3, you do not have power to your transmission harness unless you install a jumper in the underhood fuse box connector for the transmission circuits. In the truck, they are powered from the in cab fuse box for some strange reason. Found this out from having the same thing happen when I did my first install into S10 Blazer. Post up what year harness,engine tranny and computer your using, as well as fuse box. Good luck. Jim

[Bulldog88]

Im using a 02 5.3, re worked stock harness, 4l60 trans and cmputer from the same truck
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[74project]

Sorry what year is your motor, ECM, and are you using an electric pedal?
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[Bulldog88]

So the problem is solved, faulty program on the computer caused the problem got the cimputer retuned and it worked, prblem solved
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[eagleuh1]

Awesome that you got it fixed, but how did it get the wrong program in the ECM if it all came from same donor? and hope all your problems are as easy to fix as a simple reprogram! Jim