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View Full Version : 6l80 final drive ration, gearing, and tire change help



jrad12381
July 23rd, 2016, 03:24 AM
I have a 418 stroker and a 6l80 in an offroad race car the ecu and trans came out of a 2007 Yukon denali. This car and trans have gone through many build phases, and the trans tuning IE..shift points have never been right. For some reason my tuner used a final drive ratio of 4.40 and a tire diameter of 36" (when my final drive ratio is actually 5.43, and my tire measures 38.5" tall . I am now using a corvette TCM tune to utilize tap shift. When I flashed this in I changed the shift speeds to match my old tcm tune.

I want to try to change my final drive ratios so they are correct. When I do this under the TCM speedo section I can change both the final drive ration, and the tire size, but when I press apply none of the shift speeds change. I have also tried to make changes utilizing the shift point corrections tab, and I get a message that says (No transmisison settings are available
for adjustment in this calibration.)

Does anyone have any pointers, on how to apply these changes and make them change shift MPH speeds?

Thanks
Jared

joecar
July 23rd, 2016, 10:40 AM
Post your trans file.

jrad12381
July 23rd, 2016, 01:08 PM
Here is one of the tunes, I have several variations.

Blacky
July 24th, 2016, 08:29 AM
Is this what you're using to change the shift points?
20017

Regards
Paul

jrad12381
July 24th, 2016, 09:33 AM
Yes I am at that screen, but I don't get any of those parameters to populate in the middle section. I get a message stating (No transmission settings are available
for adjustment in this calibration.) I will try to re-open my tune as it looks like you were able to make the changes to my base tune I had posted.

jrad12381
July 24th, 2016, 10:26 AM
Blacky prior to me getting to the picture you screenshot I get a box that pops up when I click on speedo calculator that says

EFI live tune- digital tools for onboard vehicle electronics

Cannot create file C:\Programfiles
(x86)\EFILive\V7.5\Configuration\cal_adjust.txt" access is denied

Blacky
July 24th, 2016, 02:46 PM
The cal_adjust.txt file (which contains the list of calibrations to be updated) is stored in the C:\Program Files (x86)\EFILive\V7.5\Configuration folder.
Windows requires admin privileges for any program (i.e. EFILive) to be allowed to modify any file in that folder.
So as a quick test, try running EFILive as Administrator. To do that right click on the desktop shortcut for the "EFILive Tune Tool" and select Run as Administrator.

Regards
Paul

jrad12381
July 24th, 2016, 02:50 PM
Thanks Paul that seemed to work. Appreciate everyone's help here.

jrad12381
July 24th, 2016, 02:54 PM
Now for the next question.

When I open up parameters under the speedo section it shows H0103 final drive ration as 4.40, but when I click on the speedo calculator button it shows my H0103 as 1.11.
Is this causing the TCM to get a bad reading?