Early model 6L80e gear hunting in conversions problems

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January 23rd, 2018
Hooter

Early model 6L80e gear hunting in conversions problems

Hi Guys, Ive come across a curly one here and interested to see if others have come across it and whether anyone has a way around it.
This applies to Australian models which use the BCM to control the TUTD
When using the 2007 YPRZ e38 and the matching T43
OS ID AA
BCC 9647
OS 24239353
Cal 24239647

OK, so the problem is, when doing conversions, ie using these combos in say a Patrol or Early Holden or Hotrods or whatever, things seem to change.
I have exactly the same model in my standard factory model 07/08 Statesman with no probs.
But in a conversion, whether you have the BCM plugged in or not, the trans will hunt between 4th, 5th, and if you are lucky enough to get into 6th gear, no matter what you set the shift speeds and all the rest of it to, it makes no difference..... just randomly changes up and down gears....
I have spoken to a couple of other tuning mates about it and they have had the same problem, and the only fix seems to be to change to a later tranny or the TCM out for a later model, and then use a matching ECM to suit and retune it.
I either use the same model BCM and the VE shifter, or I have a special made Can bus TUTD controller that allows the use of any shifter, even column shifter, and it has TUTD buttons, along with a Video screen that shows things like gear position, RPM, Oil Pressure, Intake Temp, and Trans Temp.
But these only control the TUTD and if not installed or unplugged, has no effect on transmission function.....
In some cases with this early model, if you can get it into 6th, then switch to manual mode, it will hold it in 6th.... others wont.

It seems, because of early protocol, and an early design TCM, that this cant be patched or updated, and the only fix is to replace with newer, which is a bummer for new customers that have just replaced their crappy old diesel or whatever, with a not exactly cheap conversion.... and now have to spend more if they were unfortunate to buy this early model......

So before I write this model off, I thought I had better ask if anyone out there in propeller head land has found another way around this, taking into account we use quite a different BCM setup than USA, although in a conversion this shouldnt come into play too much without a BCM.
January 24th, 2018
joecar

I don't know much about swaps, but do you have a good VSS signal...?
January 26th, 2018
Chevy366

Aren't there shift kits that would allow manual shifting. My 4L80E kit came with way to convert to manual shift very easily.
January 27th, 2018
Hooter

Quote:

Originally Posted by joecar

I don't know much about swaps, but do you have a good VSS signal...?

Yes, Speed signal is fine Joe
Actually in our VE model here in Oz, we dont use the VSS out signal, as the speed signal comes from the ABS to the BCM
Holden changed this on the last and sadly recent discontinued model VF Commodore, and added the VSS circuit to Pin 16 on the TCM to the ECM,
I add this wire to all my 6L80e harnesses in conversions, along with a signal out from the ECM, otherwise there is no signal out to run a speedometer.
The TCM has an inbuilt speed sensor and uses this native data for its shift speeds.
January 27th, 2018
Hooter

No the 6L80e has completely different functions to the earlier transmissions..... a long story...
January 29th, 2018
joecar

Quote:

Originally Posted by Hooter

...
The TCM has an inbuilt speed sensor and uses this native data for its shift speeds.

Ah, I see.
February 1st, 2018
Tre-Cool

Quote:

Originally Posted by Hooter

Yes, Speed signal is fine Joe
Actually in our VE model here in Oz, we dont use the VSS out signal, as the speed signal comes from the ABS to the BCM
Holden changed this on the last and sadly recent discontinued model VF Commodore, and added the VSS circuit to Pin 16 on the TCM to the ECM,
I add this wire to all my 6L80e harnesses in conversions, along with a signal out from the ECM, otherwise there is no signal out to run a speedometer.
The TCM has an inbuilt speed sensor and uses this native data for its shift speeds.

Interesting, i'll have to look at my wiring as I put a 2010 model combo tcm/ecu in my vy ute & grab the speed from the ecu just fine.

Back to the original problem, I have experienced this issue in a conversion someone did but as it was originally tuned with hpt & i wasn't getting paid to fix it. I told them to take it back to the original tuner to get it it all reflashed when it was known to work.

Apparently sometime between the original tuner & me they took it to someone else & they messed with the tune & broke\corrupted something. Once the original tuner flashed it, it was good again.