What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[SpareParts]

I have read, The 2007 AWD does not use a VSS for speed and uses tire rotation for speed.
I have looked. The TC does not have a VSS and there is a plug where one would go.
The speedo is registering fast by about 8 mph at 40 mph. Using GPS to check accuracy.

 

[SpareParts]

EBay pic to show what mine looks like.

 

[mikez71]

Interesting, the speed difference is the difference in ratio..

What happened with the PCM Output Calibration change?
(It does say that is used for speedo and ABS calibration...)

And is ECM showing the right speed?

I wonder if you need to change the speed sensor type and speed sensor calibration.. (repTOS or serial..)
Maybe the BCM is providing the speed data to cluster otherwise...
Similar to bypassing revlimit where you need to select 'calibration' instead of 'gmlan'...

 

[SpareParts]

I think i have found the problem.
I have only been writing the trans controller.
I think i need to write engine and trans. Gonna find out.

 

[Doubeleive]

I thought you had said the speedometer was slow by 10mph... my bad

 

[SpareParts]

ok long story.
I did not realize when i opened VCM Editor it automatically opened the last opened file so i was only editing the last opened file over and over. Changing nothing really.
Running out of ideas i decided to read entire and was going to start fresh.
Once it was done reading i noticed the final drive ratio had the top two rows as 3.42(ecu) and the bottom two as 4.10(tcm)
Edited it all to be 4.10, saved and wrote the file to the TCM.
After it was done i closed the file then reread the TCM. Once it was done i opened it up and the file only showed the two trans GR.
That's when i realized i needed to write both the ecu and tcm.
After writing them both i closed file. Did a read entire and when i opened that all 4 GR lines read 4.10. Nice
Went for a drive. Speedo is more or less correct. It is still about 1 or 2 miles fast but i think now it's just tire diameter problem.

Problem solved, just needs a little fine tuning to be perfect.

 

[homesick]

ok long story.
I did not realize when i opened VCM Editor it automatically opened the last opened file so i was only editing the last opened file over and over. Changing nothing really.
Running out of ideas i decided to read entire and was going to start fresh.
Once it was done reading i noticed the final drive ratio had the top two rows as 3.42(ecu) and the bottom two as 4.10(tcm)
Edited it all to be 4.10, saved and wrote the file to the TCM.
After it was done i closed the file then reread the TCM. Once it was done i opened it up and the file only showed the two trans GR.
That's when i realized i needed to write both the ecu and tcm.
After writing them both i closed file. Did a read entire and when i opened that all 4 GR lines read 4.10. Nice
Went for a drive. Speedo is more or less correct. It is still about 1 or 2 miles fast but i think now it's just tire diameter problem.

Problem solved, just needs a little fine tuning to be perfect.

LOL, what a relief, huh? It's amazing how much easier things are when you figure them out.

joe

 

[SpareParts]

It sure is. Kinda glad cuz them the lessons you never forget.

 

[Charlie207]

Started tacking the bumper kit together, and will try to get it all welded up tomorrow.

I have to get creative moving heavy stuff in my one man band.

Also swapped on my summer wheels/tires today. From back here it with no bumper, it almost reminds me of one of those Icelandic snow rigs.

 

[89Suburban]

Drug my fat old tired ass under her to change the oil mobile 1 full synthetic and delco filter.

 

[SpareParts]

Noticed this in HP Tuners. Wonder what signals it to activate 4x4 mode.
I know on GMT800's it is just a wire from either tc or the actuator to the ecm to active it.
Wonder if the GMT900 is the same.

 

[Dirty looks]

Here ya go, Biff

View attachment 482049View attachment 482050View attachment 482051View attachment 482052


Now to go dust off the “build” thread with some details that are not all sunshine and rainbows

And thanks to Biff for the link to new sway bar end links

 

[RooTBeeRthe1st]

After a few years at this point I think of having no rear wiper or being able to pop the rear glass...I put a new wiper motor in and all is well again...just need to get the plastic interior trim for the hatch from my storage unit now to finish the job. At least the exterior is finished though. Tried re-glueing the plastic piece to the foam on the glass, we'll see if it stays.

 

[SpareParts]

Been a couple day's now and im loveing the 4.10's!
Highway milage seems un affected, still about 20 mpg.
I would have to say anyone considering it needs to do it.

 

[LSCALADE]

ok long story.
I did not realize when i opened VCM Editor it automatically opened the last opened file so i was only editing the last opened file over and over. Changing nothing really.
Running out of ideas i decided to read entire and was going to start fresh.
Once it was done reading i noticed the final drive ratio had the top two rows as 3.42(ecu) and the bottom two as 4.10(tcm)
Edited it all to be 4.10, saved and wrote the file to the TCM.
After it was done i closed the file then reread the TCM. Once it was done i opened it up and the file only showed the two trans GR.
That's when i realized i needed to write both the ecu and tcm.
After writing them both i closed file. Did a read entire and when i opened that all 4 GR lines read 4.10. Nice
Went for a drive. Speedo is more or less correct. It is still about 1 or 2 miles fast but i think now it's just tire diameter problem.

Problem solved, just needs a little fine tuning to be perfect.

I run 275/65/18 tire which measures something like 32.9" in diameter, the number that I had to enter to adjust speedo was 31.2" and now its spot on accurate to the GPS values. So if you are wanting to adjust the speedo you can either calculate the percentage difference and subtract that from the current tire diameter registered or just enter the 31.2. I was off also by 2mph and I went from 30.5 to 31.2 and that did the trick. Hope this helps.

 

[SpareParts]

Same tire size. Have not messed with it yet. I think I have 31.7 size right now

 

[SpareParts]

Something else i have noticed and i can not pinpoint why.
For some reason Cracker now seems to drive extremely smooth after swapping the diff's. Hard to explain.
I did not have any bearing noise before the swap and the old universal joint was good.
Maybe running the same rpm range but with 4.10's the engine is not lugging like before the gear change?
I don't know but it is another +.

 

[07burban88]

Put the new rims and tires on her this morning to get them out the shop so my boss didn't sell them. I also installed OEM lug locks I got from a pick a part with key

 

[lowh07]

Just ordered a stage 5 rebuild kit, case saver, pump plate from Jake’s Performance. Should be pretty bulletproof! I was going to just “send it” with the stock unit but I know it would just be a matter of time. Better to do it now. Should have the engine block back from the machine shop any day now. When that’s assembled, I’ll pull the 5.3/4L80E at once and start working on the transmission. Kinda apprehensive about doing it myself, but I think it’ll be fine as long as I’m very thorough and take my time. I’d like to be able to do it and say that I did it, and it’ll also save me a bunch of money.

 

[07burban88]

they have one for the 4l60E?