2006 Corvette "normal D" shifts great, sport/TUTD still soft at WOT only

FIXED look below for the fix

So, this is a 2006 Corvette with a BTR 2 cam. Stock stall, gear, etc. It has 120k miles on it.

The issue is a strange one. It shifts PERFECT in normal D, and in sport/TUTD at cruise, part throttle, etc. At WOT Normal shift is PERFECT. The issue is WOT Sport/TUTD. (Can't hook 1/2 and 3/4 is too fast to test). It is MUCH softer than normal. I have checked shift timing and pressures and matched them all as far as I can see in every mode to ensure no issue there.

The normal shift is the middle wot one and the sport mode is the first and last one, obviously.


Thank you for any help.

Attachment 115261Attachment 115262

FIXED: Adders in Desired output torque factor are different in special/TUTD. 0'ing them and making a table in the torque adder table only like in the newer 6L80s corrected the issue.

Attachment 115264


I felt like I wanted to give a more in depth fix on this problem, as it is just how they set up the early 6L80s and it stumped me(although I have done these before and NOT seen this issue). It is not a pressure issue, its a shift time issue...

On the early 6l80s they have Desired shift time , inertia adder, torque adder and desired output torque factor.

On the newer ones they have Torque adder, transition time inertia, and desired output torque factor getting rid of the desired shift time AND not using the desired output torque factor as much. In the higher RPM areas the newer ones have low(or 0) in the desired output torque factor, so the entire shift feel/time is done in the torque adder table for high RPM, WOT shifts

Setting the older OS with 0 in desired shift time and desired output torque factor allowed us to make a custom trans shift table like in the newer OS's in the torque adder table alone and dial that in. Problem fixed and also made the shift RPM match much more closely than before. Still not sure why some of my older ones I've done do not have this issue, but glad to have it done!

Quote:

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Originally Posted by Snowman1987

FIXED: Adders in Desired output torque factor are different in special/TUTD. 0'ing them and making a table in the torque adder table only like in the newer 6L80s corrected the issue.

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Same issue on my 2018 cammed Silverado with a circle d stage 2 6L80 w/3k stall I?m glad I saw this randomly I double checked tap settings they match the stock cal. In D all was good I?m a tu/td lifer I noticed the 1st was spongy 2nd felt like it was slipping 90% it would only shift to 3rd way after being commanded with no pedal. I had loaded some stuff on a tune template that included tcm15823-tcm15833 from earlier e67 ecm (CTSV file) I?ve read about this and obviously it went over my head. Copied/pasted these tables for the most part were just zeroed out from my stock 2018 easy as that.

Just on the subject any other parameters to note with similar compatibility issues from the earlier > late model 6L80s

None that I have seen and I do a LOT of 6l80s. Even on the newer ones certain things are 0'd out unlike the older ones.

Glad it was able to help you out! What this community is all about