4L80e swap problems...PCM/tune related?

[Scream]

Long story short...I'm swapping an 80-e from a 2003 6L truck into my 2001 Sierra (originally 4.8/60-e.) Here's my post from another board outlining the problems. Anyone have any ideas? Allan, is this something that you could fix for me?

I talked to John @ Speartech today, and he told me that if I have the correct file, that LS1EDIT *will* reflash the PCM (i.e. I don't have to send it to him.) The PCM accepted the file that I was sent, but the truck still won't shift into reverse. As a matter of fact, we hooked a Snap On scan tool to it, and the PCM is telling the tranny to be in 1st gear regardless of which gear is selected with the shifter, including reverse.

I sent the file to John today and left him a couple of messages, but after our initial conversation this morning he hasn't been able to call/email me back. Can I email the file to anyone and have them check it w/ EDIT to make sure that it's the correct one? That the segment 1 ID is correct, etc etc?

Does anyone have any other suggestions? We've checked, rechecked, and triple checked the wiring and it is all spot on. I **have** to get this truck off of the lift soon...it's waaaay to heavy to push in and outta the shop. Any help at all would be greatly appreciated. WHY CAN'T THIS SHIT JUST WORK?!!?!?!?!? [/b]

[RedHeartbeat]

Can you just flash it back to your stock tune to get it off the lift? It should run and drive on the 4.8, just don't drive it long since it will be lean.

[Scream]

Originally posted by RedHeartbeat@Nov 8 2005, 12:17 PM
Can you just flash it back to your stock tune to get it off the lift? It should run and drive on the 4.8, just don't drive it long since it will be lean.

The motor isn't what I'm worried about. The PCM is telling the transmission to select 1st gear regardless of which gear is selected with the shifter. Even Park. If I select "R" on the shifter, the PCM says "okay, that's 1st" and the tranny goes into 1st. It's even in 1st when it's in park...if you try to rev the motor, you can tell there's a load on it. the tires just don't turn because of the park mechanism.

[RedHeartbeat]

Is this a new wiring harness you've installed or just a custom tune for the 6.0L engine? You mention speartech is why I ask. Is the transmission your original one from the 4.8L?

[Scream]

Actually, both. I have the Speartech harness and have a new EDIT file from Carputing. The transmission I am putting in it is a 4L80-E from a 2003 6.0L 2500 truck.

[chrisj6]

well there is an option on the pcm that is "PRNDL" equipped, just a random guess but this could be set to "no". I know its in system tab of hptuners but i have no idea where it would be in edit.

Chris

[RedHeartbeat]

I assume that they built the harness with the 4L80E in mind. I wonder if they got the wire for the 1st gear solenoid in the wrong location in the PCM and it's getting signal all the time due to it. I'd definitely be burning up the phone line with them right now.

[RedHeartbeat]

Was this your PCM that was working fine before or is it one of theirs? I wonder if it's just a bad PCM.

[Scream]

Originally posted by RedHeartbeat@Nov 8 2005, 05:43 PM
Was this your PCM that was working fine before or is it one of theirs? I wonder if it's just a bad PCM.

Yes, this is the PCM that I've had in the truck and was working fine until the tranny swap.

[RedHeartbeat]

What really has me thinking is that it is trying to pull fwd while in park. If the engine came out of a wrecked truck, I would drop the transmission pan and check the functionality of the shift rod in the valve body. the linkage may have broken or bent in the crash. The shift solenoids don't do anything but tell when to shift from 1 to 2 to 3 and then 4. They don't engage the transmission into drive.