4L65 not engaging

[HwyStarJoe]

I'm out of ideas and would love some pointers on this issue.

Swapped an '06 GTO LS2\4L65-e into my '69 Camaro and I'm having trouble getting the trans to respond.
The TCU has 12V on Pin 31, and the TCC signal is connected to the brake light switch.

The dipstick reads fluid at the Cold area while checking it at idle in Park. I filled it with Dexron VI and run it up and down the driveway shifting through all of the gears.
It acts like a trans that doesn't have enough fluid. The engine and trans have never come apart from each other so whatever fluid was drained either dribbled out the tail, or was dumped when I did the filter change. The cooling lines have never come off either, and go to a stand-alone cooler.

It moves in Reverse fine. In all other gears except maybe 1, it's sluggish as though it doesn't have enough fluid. In 1 I can actually feel the trans shift and the car moves somewhat responsive but still not as it should.

My ODBII scan software is only a basic version and won't show me the TCU. But I am getting a U0101 Lost Communications With TCU code. I don't know if this is because my scanner won't read it, or because there's an issue with the TCU. I have the full GM software package coming which should tell me one way or the other about the TCU.

Any ideas why the trans is acting this way?
Thanks all

[Steve Chryssos]

That sluggish, "not enough fluid" sensation more than likely means it's in limp mode, which means 2nd gear only. There are a million reasons why that could be the case. But there are some easy "external" checks such as:
-- Does the fluid smell burned?
-- Check case harness connections. Literally unplug and reconnect the main case plug and vss plug at tail.
-- Are you surely getting a TPS reading? Grab a multi-meter and check it.
Beyond that, while your waiting for software, you might as well drain the fluid and pull the pan to see if there are any major bits lying around. That will also be a good chance to freshen the filter and possibly the internal harness, if you're feeling spendy.

[HwyStarJoe]

Thanks Steve... that gives me a couple places to check.

The fluid is 100% new. I did a filter change, then kept adding till it was at the Cold area.
I sort of suspected Limp Mode. That tells me the TCM has problems.

The only change I made to the trans was removing the Park\Neutral Safety switch assembly on the gear selector shaft, to install the shifter linkage for my shifter. My shifter has it's own NS switch.
I could not find anywhere that tells me what to do with the circuits of the connector to the P\N Safety switch. It's just dangling there for now.

[Steve Chryssos]

I humbly admit to avoiding the OE trans control, so I can't speak to the NS switch and it's impact on Limp Mode. With that said, you might piggy back the wiring onto your Hurst connections. Along the same lines, we don't use brake switch for TCC control with the aftermarket TCU's They're all based on VSS. The last thing we want as pro-touring enthusiasts is for lock up to disengage every time we tap the brakes. Are you sure the OE scheme requires a brake switch? Maybe that's confusing the TCM. Just guessing there. Like I said, if this were an aftermarket controller, we could help 100%.

In the meantime, do all your tests with the rear wheels off the ground. Axle on jackstands and the car fairly level. No sense putting load on the trans while you figure things out.

[HwyStarJoe]

...we don't use brake switch for TCC control with the aftermarket TCU's They're all based on VSS. The last thing we want as pro-touring enthusiasts is for lock up to disengage every time we tap the brakes. Are you sure the OE scheme requires a brake switch? ....
In the meantime, do all your tests with the rear wheels off the ground. Axle on jackstands and the car fairly level. No sense putting load on the trans while you figure things out.

Not at all sure. But I've never been led to believe otherwise. The ECU and TCU have VSS signals between them, so I can disconnect the brake switch and see what happens. But it shouldn't come into play until I step on the brake pedal anyway.
Keeping the wheels off the ground is a good idea.

Thanks Steve

[HwyStarJoe]

798027980379804

Here's an update after troubleshooting... I've posted this elsewhere as well.


I'm having issues with the TCU communicating with both the ECU and ODBII. This seems to be causing the trans to operate in Limp Home mode.
All harnesses are from the donor car and have not been removed and replaced from either the engine or the trans... ever. I left everything where it was.

What I really need is the GTO 4L65-e wiring pin-outs for the TCU.
The wiring diagrams I have conflict with what's actually here... and seem to be for the same year Corvette, not the GTO.

The diagrams "ATC Schematics ECM,TCM Power and Ground" and "ATC Automatic Trans Controls" do not agree.
http://www.ls2.com/boggs/LS2/clutch/a4tranny08.JPG

http://www.ls2.com/boggs/LS2/clutch/a4tranny06.JPG


The ATC Power and Ground schematic shows power to the TCM as constant 12V on Pin 32 on an Orange wire. This is true... Pin 32 on my TCU is an orange wire.
It also shows Run\Start voltage on Pin 31 on a Pink\Blue wire. This is also true that Pin 31 is Pk\BU.

The Trans Controls diagram disagrees and shows Pin 31 as a BU\WH wire. There is no BU\WH wire in the TCM harness. There is however two BU wires. Neither is Pin 31.
I believe that diagram is for the Corvette only, correct?

Like I said, my scanner fails to connect to the TCM, and I get a "Lost Communications With TCU" error when reading the ECU, and the trans will not operate correctly.
I have constant 12V on Pin 32 at the TCM.
I do not have switched 12V on Pin 31.

But as I checked voltages, I was showing a constant 12V on Pin 31! I traced it to the brake light switch that I wired for the TCC signal on Pin 25 to unlock the torque convertor!! How can that possibly be since that signal is supposed to be on Pin 25?? I used these diagrams to wire it and obviously Pin 25 on the GTO TCU is something else... not TCC. The wire that I thought was Pin 25 is brown\black.

If I put my foot on the brake, the 12V went away on Pin 31 at the TCM. That's how I knew it was wired wrong.

I disconnected the brake switch wires and the 12V is no longer on Pin 31, but there is a residual voltage less than 1V, which is also present on Pin 1. I don't know what the correct signal or voltage is for Pin 1 because the ATC Controls diagram is incorrect for my trans. At least I believe it is.
That also leads me to believe I wired the TCC signal wire incorrectly. It's not really Pin 25 on this trans.

One more question...
In the other ECM,TCM Control Relays diagram, the ECM and the TCM have a yellow "Accessory" voltage signal. I assume I should have switched 12V on the yellow wire to Pin C1-18 of the ECM, which also feeds it to Pin 11 of the TCM? I trust that diagram... I think!
Could that be my issue? I do not have the ECM Pin 18 yellow wire connected to 12V.

I hope and pray I did not smoke this TCM.

Any help would be great! I'm THIS close to driving the car now.
Thanks all!

[kochevy67]

Do you have the body control module , if not that is your problem. I had the exact same issue with my Chevelle. There are two wires that need to be tied together to communicate the ECM and the TCM. The BCM is the go between and needs to be by passed to eliminate this problem. PM me if you still have problems. I can't remember which two I will have to look under my dash to let you know. I had to call John at Speartech and he knew that problem over the phone.

[kochevy67]

Or you can just call John at Speartech he is a wizard at this stuff. He wouldn't take a dime so I sent him a gift card because I was ripping my hair out over this.

[HwyStarJoe]

You hit the nail on the head.
I had it figured out last night... the modules weren't talking to each other and it's because the C1 branch of the ECM which is also the DTC branch didn't include the twisted pair for the TCM.
And it turns out most of the power I was missing, including the interior leg of those two wires, was on the BCM branch that I had tied out of the way.

A little time with the soldering iron and heat shrink and I'm good to go as far as the computers talking. I just need to find the correct TCC signal wire(s) to correctly wire the brake switch so the torque convertor codes go away.
It's still in Limp Mode though... only have reverse and second gear. Hopefully when the torque convertor codes are cleared it'll fully function.
Would Fuel Trim Lean Bank 1 and 2 codes put it in limp mode?

Thanks man.

[kochevy67]

I am not 100% sure, but it probably would because it is a fail safe to protect the drivetrain. I wold clear all the codes and go from there, if you stil can't get it then I would highly suggest calling John from Speartech if you can get a hold of him.

[HwyStarJoe]

Thanks man... I'll do that.

[kochevy67]

I looked out the schematic and the two wires you have circled are the ones that I was referring to.

[HwyStarJoe]

Some progress... not much.

Re-connected the brake light switch to the wire between TCM Pin 25 and transmission Pin T.
At least now I have all forward gears, but I can tell some solenoids aren't working. I haven't checked power on E yet. That's my next step.

[HwyStarJoe]

*edited*
Some progress...
I do not have 12v at the trans Pin E if the connector is unplugged from the trans. With the trans plugged in and I check continuity between BAT+ and any of the solenoid wires at the TCM, I have continuity. That tells me they are all hot wired for power all the time somehow, which is a good thing. I know they're ground controlled by the TCM.
I have ACC power on 31 and BAT+ on 32. But no BAT+ on Pin E when the trans connector is unplugged. Obviously thats because it gets it's power thru the TCM and not directly.

The issue I have when I put it in gear is a 1 second delay before it catches a gear... any forward gear. And it feels like it's shifted into gear, not slid slowly as if the fluid were low.
I can't drive it around the block yet to see if it learns or if the codes go away... but I can do that once I drop the exhaust. I can only go back and forth in the driveway at the moment.
The codes I'm getting are P0787, P2764 and P2769. All torque convertor and shift solenoid codes.

[Kenova]

The only change I made to the trans was removing the Park\Neutral Safety switch assembly on the gear selector shaft,.........
I believe this switch is more than just a neutral safety switch. Put it back on and adjust it properly.

Ken

[HwyStarJoe]

It can't go back on because of the Shiftworks bracketry. My original horseshoe shifter handles the reverse lights, and power to the starter.
I was wondering if some of the wires in the P\N safety switch should be jumpered to correct any issues having it unplugged would cause.

[kochevy67]

Did you call John? I'm telling you he will answer your questions and save you a lot of aggravation.

[HwyStarJoe]

Turns out its been wired correctly.... took it for a spin and decided a longer run had no risk.
:)
I'm getting used to the shift pattern. I'm gonna have to get used to leaving it in 3rd most of the time unless I'm above 40 or so.

one thing that bothers me is how much lag the trans has from a stop. once the exhaust is on and the cars been inspected, I'll have it tuned and play with shift points.

thanks all!

[rocketrod]

Turns out its been wired correctly.... took it for a spin and decided a longer run had no risk.
:)
I'm getting used to the shift pattern. I'm gonna have to get used to leaving it in 3rd most of the time unless I'm above 40 or so.

one thing that bothers me is how much lag the trans has from a stop. once the exhaust is on and the cars been inspected, I'll have it tuned and play with shift points.


thanks all!
That's great news! If you have HP you can use the following links as a great reference for tuning your trans that I found very helpful

The following link list a buy it now option, but just download the Transmission Shift Rate File spreadsheet.
http://ls1tuningguide.com/index.php

If you aren't a member of HP Tuners forum, sign up and read through the following How To....

http://www.hptuners.com/forum/showthread.php?31591-How-To-4L60-65E-trans-tuning-Shifting-TCC-TM-(w-Pics)

[HwyStarJoe]

Thanks...
Wish I could afford one right now!