Stand alone? Desperate for a solution.

[Ishmael]

Hey guys
I've been dealing with a trans problem for over a year and its the only thing stopping me from driving my car. I bought a harness for a 06 LS@ and a 4l65e. I'm using 2007 silverado computers for it. I can't get the car to go into 4th and only rarely into 3rd. It stays in 2nd unless I downshift manually. The trans needed to be rebuilt after only driving it into the alignment shop. I had it built when I bought it too.
The company that sold the harness said the problem was the trans was a 13 pin connector so while the trans was being rebuilt they put in the internals for a 15 pin connection. Its a transmission shop not just a regular garage so I assume they know what they are doing. Still no shifting.
The company said I needed to clear the codes that came up with a tech2 reader. I had a GM place clear the crank position not found code but they couldn't clear a Transmission Range Switch Circuit and Output Speed Sensor Circuit Low codes. The GM guy said sometimes there's a parking brake switch that needs to be held to clear it but there isn't such a thing on my harness and the PRNDL switch is there but there was nothing in the harness for it and the computer was supposed to have that switch deleted from the tune. I trust the harness company as they have been great trying to help me.
Its got to be the harness, computer or trans. Is there a stand alone harness that I could use - just disconnect the TCM and plug in the new harness? I was thinking http://www.gmperformancemotor.com/parts/19302405.html but maybe there's an easier, cheaper or better alternative? Or should I pull the trans and get a different one. I've put too much into the trans but I don't care at this point.
thanks
Scott

[csouth]

That looks like it still integrates with the engine ecm and only E67 are compatible. Do you know which ECM you have currently? If it were me I'd probably use something like FAST EZ TCU at this point. Look up FAST EZ-TCU on YouTube and you can see how simple it is. You would need the TPS harness also to link the engine and the TCU, but there is a link to it at the bottom of their page.

http://www.tciauto.com/tc/ez-tcutm-transmission-control-unit-gm-4l60-4l65-4l70-4l80-and-4l85e-to-09html/

[Ishmael]

Thanks for the input Chris,
I'm using a factory ECM at this point. TCI said they would make the controller for whichever pin transmission I had . As long as it doesn't have to somehow match up with the ECM I should be okay.

[csouth]

Thanks for the input Chris,
I'm using a factory ECM at this point. TCI said they would make the controller for whichever pin transmission I had . As long as it doesn't have to somehow match up with the ECM I should be okay.

Yeah, it only takes the reading from the TPS to know when shifts are necessary. The TPS Y cable they sell should take care of that. If you still want to use the Supermatic setup, just verify you have the E67 ECM. What is ls engine originally out of?

The good thing about the TCI unit is you're tuning it yourself as much as the handset allows. You can change shiftpoints and firmness as long as the internals can handle it.

[Ishmael]

The engine was from an 06 vette and the trans unfortunately was from a Tahoe or similar but only had 13 pin.

[csouth]

The engine was from an 06 vette and the trans unfortunately was from a Tahoe or similar but only had 13 pin.

I'm assuming its the e67 for the LS2. I'd still try the FAST.

[Ishmael]

I've got a few wires to check left. One of the codes was for the OSS though it wasn't a problem in the past. Once I get through that I think I'll try to TCI unit.
thanks again

[Jrwade]

I have a like new fast tcu that I will get ride of for a good price. Pm me for details.

[cpd004]

I went through something similar and it turned out to be the harness. Getting the stand alone might get the trans working but you never know what will pop up on the engine side. You might be masking one problem and causing another. Which harness manufacturer are you using?

[icemanrd19]

how much is the stand alone? seems like a lot of trouble so why not go to a t56 mag?

[csouth]

how much is the stand alone? seems like a lot of trouble so why not go to a t56 mag?

A stand alone controller is not more than $700 including the y harness, T56 magnum is 3k without a clutch, pressure plate and flywheel.

[csouth]

I went through something similar and it turned out to be the harness. Getting the stand alone might get the trans working but you never know what will pop up on the engine side. You might be masking one problem and causing another. Which harness manufacturer are you using?

How a does a stand alone TCU mask a problem on the engine side? The engine is still being controlled by the GM ECU.

[Ishmael]

No stick on this one. I want my wife to be able to drive it ----- someday. All the pins were in place in the connector to the speed sensor and the tcu. One of the wires on it had continuity - the other didn't. I don't feel like unwrapping the harness and I can't figure out how the wire would be bad. I don't want to mention the company because they have worked through a lot of stuff with me. There was one wire switched around on the MAF but otherwise they have been really patient and I've learned a lot about wiring.

[cpd004]

Mask might've been a poor choice of words. I threw a bunch of time and money with a local tuner at my original harness before finally giving up. Sent it back just before the year was up and switched manufacturers. Huge pain in the ass. It was completely different with the harness. It shifted as it was supposed to and ran right. At one point, I too looked into stand alone with the old harness. I'm glad I didn't go that route.

[Ishmael]

I know what you're saying. The harness is the only part on the car that hasn't been physically removed 2 or 3 times at this point. When you think of how much a standalone is, it isn't that far to upgrade to a completely new harness.

[csouth]

Scott,

My only suggestion to you would be to verify the connector pin out before you invest in any new harness Full engine or trans standalone just as TCI suggested. For me, wasting money is never an option...:banghead:

[cpd004]

I know what you're saying. The harness is the only part on the car that hasn't been physically removed 2 or 3 times at this point. When you think of how much a standalone is, it isn't that far to upgrade to a completely new harness.


I wish you the best of luck. I know how frustrating it could be. Luckily I made it just in time to return my original harness within the year for a refund. They too were extremely helpful in trying to figure out the solution, but were unsuccessful.

[Justin@Speartech]

Scott,
The issue could be in the harness or computer tuning. If the harness manufacture or tuner didn't flash/pair the ECM/TCM up together with a proper OS then you can certainly run into an issue. Most common issue the trans punches you in the gut when it shift at full line pressure or the trans remains in 2nd gear. We can flash the ECM/TCM for your setup if you desire. I realize this is an older thread but if you still need help give us a ring.

[Ishmael]

I'm still having issues with it and yes it chirps the tires going into second gear even at part throttle. I still haven't tried to track down the wires causing it to not lock up in 4th. The other day it rained. I parked the car for a while and when I went to leave the throttle didn't work. I unplugged the battery and it went back to normal. Then about 5 minutes later it slowly stalled. Repeat with the battery and back to normal. Haven't had a problem in the dry but I'm starting to think I should have taken the replacement harness when I had a chance.