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View Full Version : Weird shift flare T76



pinstripebob
July 3rd, 2023, 12:49 PM
Hi all,

I played with shift points in my wife's 2012 Cruze a year or two ago, and there is a very specific condition that causes an odd up/down/up of RPM. It's easy to replicate in our neighborhood, but around town it's difficult with traffic.

I finally had time to do some logging, I got it around frame 19,100 in 3rd gear in the attached log. I thought it might be the TCC locking/unlocking, but looking at the log I almost think 3rd gear isn't fully engaging.

Could someone have a look at this and let me know what your thoughts are? Typing this out, I may flash the stock tune and see if I can replicate it with another log.

Much appreciated!

pinstripebob
July 3rd, 2023, 12:51 PM
Staring at it some more, it might be the shift from 3rd to 4th. It looks like the TCC unlocks as it goes to 4th, RPM has a sudden rise even though it shifted up, then TCC locks and RPM comes down a hair.

pinstripebob
July 5th, 2023, 04:28 AM
Figured it out, my 4th gear TCC release crossed my 3>4 shift line at just the right spot. Uncrossed it, all good. If anyone comes across this thread with the same issue, my TCC was locked during light throttle acceleration, but it briefly unlocked after shifting into 4th then locked again. Made for a weird RPM fluctuation.