strange acting T42 4L60E combo with 4wd tun file

[harascho]

I made some runs this afternoon.....

The speed is ok in low range...didn't expect anything else with the VSS in the transfercase tailhousing.

The shifts appear at about 3500rpm... when I revved it to about 2800 - 3000rpm and lifted the throttle a bit the tranny shifted.
I attach a log file but as I did my first data logging today don't expect miracles from it...

Harald

[VEGASROBBI]

Here is my info;

VIN 2GCEK13M071547739, 5.3 LH6 from a 2007 Silverado.
E38 ECM OS 12614088, Calibration 12614085
4l65E Transmission
T42 TCM OS 24239036, Calibration 24237445
I am not running a BCM.

The engine, transmission, TCM, and ECM are all from the same vehicle which was a 4WD. IM using the original wiring harness from the same vehicle.
My Transfer Case is a NP208 from an early Blazer.

Harold, I think that is the point. Your VSS will always read correctly while in the TC; but, until the ECM/TCM knows it is in 4 lo, they will try and shift as if they are in high range.

I see no 4 lo shift table available. In my tune under "Drivetrain" 4WD is selected. Then the 4 lo ratio is specified, say 2:1. EFI Live reads "4WD Low gear ratio, used to adjust the transmission output speed ratio when in 4WD Low."

So IM guessing in 4 lo the TOS is used to calculate shift points, not the VSS.

Robbie

[PSWired]

@ Patrick: Wasn't that a 2007 5.3 LMG with an ECM and 2009 OS or am I confused 'cause it's too cold over here?
And just to be very sure, I think I asked before, that 4wdlow signal to the ECM is a low active signal (low when in 4wdlow)

Harald

Yes, the engine hardware is 2007 model year, the ECM is just loaded with a 2009 OS and calibration.

[harascho]

Robbie, that's exactly what my tun says:

see:



Harald

[gmh308]

No I'm not.

TCM, ECM and engine came from 2wd applications only the BCM and tranny were 4wd.

I thought that there is no hardware difference in the components (ECM, TCM..) between 2wd and 4wd this is just a matter of the OS and calibration?

I have Patricks OS and calibration in my ECM (his ECM was 4wd..and had the same OS..) and now I am fighting with the TCM 4wd tunes...

The more I dig into it the more confusion is in my head....

Harald

Yes this is a confusing situation, but i think you will need the ECM and TCM to match the BCM based on a VIN.

[harascho]

I must agree. So I planned a visit to a German Opel/GM Dealer to get the latest updates for my ECM / TCM and BCM.

I looked up for a suitable 2007 Tahoe on ebay motors ( same configuration of engine , tranny and 4wd)
Took this VIN and ran it in TIS. I think this way I will get some matching OS and calibrations for ECM, TCM and BCM.
I also looked into 2008 Tahoes, but I think I will better choose the 2007 system.

In a few hours I will know more...

Harald

[harascho]

As I wrote in my last post I went to a GM dealer to get all the TIS updates which were avaiable for that 2007 Tahoe I have choosen as a base line. (Same engine /tranny combo as mine..).

All went fine, and now I have matching OS and calibrations in ECM, TCM and BCM.

The first testdrive was interesting. Again that strange acting not shifting tranny in 2hi. No part throttle shifts no TCC lockup. Then I tried 4wdlo and that was even more interesting, 'cause the tranny was shifting quite normal. For me it seems the speedo was only half of the real speed in 4lo but I could be wrong with this.

For me it's obvious that I might have mixed up the 4wdlo signal to the ECM. I think I wired it as a low active signal (low when in 4wdlo) but I guess it's worth a trial wiring the 4wdlo signal as a high active signal.

Harald

[VEGASROBBI]

Harald, does sending the 4 low signal have any effect on the ECM?

I recieved my new Transmission Output Shaft VSS today, I will it install it this weekend.

Harald I uploaded some pics of my project for you, check them out.

http://s418.photobucket.com/albums/pp265/VEGASROBBI/

[gmh308]

Harald, does sending the 4 low signal have any effect on the ECM?

I recieved my new Transmission Output Shaft VSS today, I will it install it this weekend.

Harald I uploaded some pics of my project for you, check them out.

http://s418.photobucket.com/albums/pp265/VEGASROBBI/

One of the purposes of the 4WD Lo input to the ECM is to change the speed limiting number.

[harascho]

Hi there,

I had some time for a few trials. Fresh from the GM dealer I have a matching set of 2007 4wd Tahoe 5.3 LMG 4L60E files in ECM, TCM and BCM.

4wdlo works, tranny shifts nice. 2hi doesn't work no part throttle shifts no downshifts, I only realize one shift at all.

Ok I built a harness where I could change the logic of the 4wdlo signal which goes to C1 pin 2 of the E38 ECM. I now can change the 4wdlo signal to active high (12V) or active low (GND). I also checked the ECM tune for correct tire size, gear ratios and 4wd type. Then I set the speed limiter to 170km/h and the low range speed limit to 70km/h. The T42 tune file has the same tire size settings. After flashing both controllers, the first testdrive was a disapointment: 2hi not working, 4lo working, no matter what logic setting I use for the 4wdlo signal. I went back to a 2wd tune (my t42 came with this one) And did a second check... funny I ended with the speed limiter cutting in in 2 hi at 70km/h and guess what, it did so no matter what logic setting I used for the 4wdlo signal.

Next test.. I did a full flash of the T42 with the tune file of the matching set I described above and checked that:

Transfer Case Ratio TCRATIO :1 Transmission 2 GM.TCRATIO PID

but no matter to which controller I connected that PID gave me strange values. If I look into the ECM that value is 8.00 : 1 and If I look into the TCM I see 2,65:1 and that doesn' change with 2hi or 4lo at all....

any ideas are very very welcome....

Harald