Applying car OS to tahoe w/T42

[InTruckDesign]

As the title says, I am looking at switching the OS in my '07 Tahoe T42 4L60 w/2600 stall to the f-body OS mostly for the ability to keep the TCC locked during coast/0%tp. It gets annoying at times especially in stop and go traffic. I am definetly a newb at switching OS's is it as simple as finding a car with the proper OS and running a script over my stock tcm file??

[joecar]

My understanding is that the F-car OS (engine/trans segments) won't flash into the T42 (trans only segments)...

I'm not sure what the TCC coast behavior is with the Y-car T42... if it keeps it locked then try that (if OS is compatible with your TCM).

[InTruckDesign]

Thanks, I found some of that after some more reading, but haven't found anything on the coast behavior either...where do you recommend I search for a similar y-car T42??

[joecar]

I think the 2005 Corvette had a T42... might ask on the Corvette forums about the TCC coast behavior speficially with a T42... but then it still has to be determined if that OS is compatible with your T42.

[InTruckDesign]

Hmmm...looks like you gave me some work/research to do...I thank you old wise one!

[ScarabEpic22]

Use an 06 GTO or Holden Commodore T42 file. Basically you need a car T42 OS instead of a truck OS, Ive got a few files I pulled from HoldenCrazy.com but havent had time to copy my T42 settings into the GTO file yet.

[joecar]

Do the GTO/Commodore 4L60E controllers keep the TCC locked on coast...?

[ScarabEpic22]

Do the GTO/Commodore 4L60E controllers keep the TCC locked on coast...?

At least the T42 ones do, so I assume the rest do as well?

[InTruckDesign]

Just wanted to update this...I haven't located a trans. segment that will work with my tahoe, yet. What I did do to keep it from locking/unlocking in stop and go traffic is I only have it lock in 4th. By doing this it has helped out a lot, most of the time I was only in 3rd when it happened. I am pretty happy with it, but will continue my search for the proper car trans. segment.

[ScarabEpic22]

Does it mess up your cluster readout (ie read you're in 1 while you're actually in P)? Im on a quest for the same thing on my TBSS, the files I have dont seem to work with my 08 TBSS, worked just fine on my friends 07...

[InTruckDesign]

Erik, my cluster readout has not changed, but I'll keep an eye on it. Driving it for the past couple days I am really liking it being unlocked in 3rd, the engine definetly stays up in its powerband and the butt dyno says it's quicker. I'll have to run some logs and do some tests to verify it.

[ScarabEpic22]

Ok good to hear, when I used a GTO TCM OS my cluster gear selector messed up and stayed in "1", I had 3rd gear (limp home mode I think). Only drove around the block and then flashed back to my TBSS TCM OS because I didnt want to mess my trans up. If you're running the stock OS then you wont have issues with the cluster.

Ill look into doing that, I dont think my TC ever locks up in 3rd unless I have the selector in 3 not D. I want to run a car OS so that when I lift my foot off the gas to slow down for a second on the highway that my TC doesnt unlock then relock once I get back on the gas.

I have some 08 Holden TCM OSs that Im going to try, if anyone has a suggestion for a 4L60-65-70E car TCM OS from 2008 please let me know!! Really wish the ECM <-> TCM comms were more generic like the LS1 PCMs so we can run whatever ECM OS and whatever TCM OS we want.

[Shupe]

I have some 08 Holden TCM OSs that Im going to try, if anyone has a suggestion for a 4L60-65-70E car TCM OS from 2008 please let me know!! Really wish the ECM <-> TCM comms were more generic like the LS1 PCMs so we can run whatever ECM OS and whatever TCM OS we want.

Subscribing to this thread… I too have been looking for the TCC to behave this way.

[Shupe]

Any updates on keeping the TCC locked while coasting above the release parameters?

[ScarabEpic22]

Unfortunately no, Shupe Im going to reply to your PM in a few minutes.

It seems to be a delicate mix, you have to pair a car TCM OS with a truck ECM OS that can understand the CAN messages the TCM is spitting (and vice-versa). Otherwise you get 2nd gear only and no gear selector.

[InTruckDesign]

I am still running with 3rd unlocked as aeound town it just makes it a more pleasant driving experience as I typically only use 4th when on the highway. With 4th being locked at cruise on the highway it still does unlock when I lift then relock, but it is not annoying as I have it tuned now to feel like an additional gear shift.
I have found that trans. tuning is definetly varied from person to person and you just need to get it dialed into your own liking. All the time I spend on it will go out the window soon as I will be adding a front mount turbo within the next couple months. Ugh.

[Stroked250r]

Bringing an old thread back to life! I too have a 2008, silverado with an E38 and T42 combo, and I'm trying to find a car OS that will work with the truck E38 and also keep the converter locked at 0% throttle. I tried a 2005 corvette t42 os and 2006 gto t42 OS with no luck, didn't have reverse lights, no gearshift indication, I didn't even attempt to drive the truck.

Now I did find a 2008 holden commodore (middle east) T42 OS that mates to an E38 ECM, so I decided to try that. I updated all of the tables to match my latest tune, performed a full flash, and all seems to be working except for my speedometer, the ECM VSS PID is showing 255 km/h on the scantool but my speedo stays at zero. The trans does shift through all four gears and does remained locked at 0% throttle, however it feels like something is dragging while driving around at slow speeds, almost as if the brakes are applied, however it might be all in my head due to not being able to determine my speed.

Does anyone have suggestions or know how to get the truck T42 to keep the converter locked at 0% throttle? I know this has been brought up a few times, just thought someone might have found a workaround by now. Thanks.