6l90e 37 inch tires speedo & shift points

Trying to get speedo and trans shift points changed for 37 inch tires.
ok I can get VSS on the logs and the dash to read correct but after 30 hrs of trying I can not seem to figure out how to get the shift speeds correct with having the vss set correct in the t43 controller
I used the speedo calculator witch got me close on t43 logging ,then figured out how to make the dash read the same but the shift points are off like 8 mpr on the 4to5 and the 5to6 shifts
I tried every thing I can come up with has any one ever fixed this before?

I have never been able to get it correct for anything bigger than 33's. I do not think you can get it correct for 37's. Is it not throwing ABS codes yet?

Has a abs light on yes guessing some one pulled a fuse,after 35 hrs i gave up there was know way do make vss and target shift points in line,i could get it if i droped my target shift points 8 mpr, I am talking part throttle shift never got to wot shifts,I tried some thing else took 15 mins to fix it pretty up set about it, 3rd problem in last 6 months thats cost me over 100hrs labor

The ABS light is most likely on from the tires size not matching in the ABS module and the actual tire size. being different. Currently I do not know of a solution for tires over 33.

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Originally Posted by minytrker

The ABS light is most likely on from the tires size not matching in the ABS module and the actual tire size. being different. Currently I do not know of a solution for tires over 33.

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There would be no good way to fix the abs anyways with 37 inch tires the abs calibration wouldn't be any good, the fact is the the speedo tire correction. Doesn't work right to fix the shift points where they meet there target mpr,but it's do able because after 3xhrs it took me 15 mins,with hpts I haven't uzed in 8 years,tired of wasting days of work over old problems ,last 3 tunes I have done had problems that wasn't taken care of some how when there old ecms