6l80 3-4 shift flare
Thread Starter
2nd Gear
Joined: Apr 2023
Posts: 2
Likes: 0
From: 57049
6l80 3-4 shift flare
My 2010 Grand Sport has a 3-4 shift flair usually for the first one or two shifts from 3-4. After that, no flair. Fluid and filter was changed with no change to the issue. Is there a fix for this or do I have to rebuild the transmission?
Race Director
Joined: Sep 2007
Posts: 16,557
Likes: 2,108
From: Peoria/Phoenix AZ
C6 of Year Finalist (performance mods) 2019
Try adding 1/2 to 1 quarts of trans fluid. If there is not enough fluid, it takes some driving time to gain the heat needed to expand the fluid. The fluid change specs require the car to be level and the fluid temp to be between 86 and 122 degrees. Then shift through all gears and pull the drain plug to remove the excess. Do a search with the terms "transmission fluid change HOXXOH"
It's a bit better to have a little extra fluid than not quite enough.
It's a bit better to have a little extra fluid than not quite enough.
Instructor
Joined: Apr 2000
Posts: 196
Likes: 32
From: Il
Bominator - a shift flare is a temp slip when the trans shifts gears.
maeschen - My ctsv has a 6L90 is in with the same issue. First time out of the driveway it flares/slips on the 3-4 ****. After that it never happens again during that drive. I tried the extra fluid with no luck. It drives me nuts to this day. I even had the trans rebuilt. Still there. I did read something on a GM truck forum that it's a common issue. Something to due with a seal not fitting properly in a bore. Once the trans come up to temp everything expands and the issue goes away.
Hope you have better luck solving than I did.
maeschen - My ctsv has a 6L90 is in with the same issue. First time out of the driveway it flares/slips on the 3-4 ****. After that it never happens again during that drive. I tried the extra fluid with no luck. It drives me nuts to this day. I even had the trans rebuilt. Still there. I did read something on a GM truck forum that it's a common issue. Something to due with a seal not fitting properly in a bore. Once the trans come up to temp everything expands and the issue goes away.
Hope you have better luck solving than I did.
Thread Starter
2nd Gear
Joined: Apr 2023
Posts: 2
Likes: 0
From: 57049
Yes! That's how mine acts. First and sometimes the second shift from 3-4 out of the driveway will have a flare. From what I've read, it isn't slipping. The 4th gear clutch isn't engaging. It's like a slow motion shift, hence the engine revs (flares) in between the two gears. I think it's a software issue. Reports of rebuilt transmissions being installed and still having the same issue. Flashing the TCM with the latest software and setting it to do a relearn has reportedly fixed the issue. The issue doesn't seem to be talked about since 2017 or 2019 in various forums so I assume that there is a solution to this issue and I don't think it's rebuilding the transmission. .
Instructor
Joined: Apr 2000
Posts: 196
Likes: 32
From: Il
When I had mine rebuilt, they updated the programming, they even tried custom setting with HPTuners. Nothing worked.
I talked with Bowler Transmissions about it after the initial rebuild. They said they thought they could fix it, but it would require a bore and re-sleeve of whatever area had the original manufacture issue. I didn't want to go thru all that again for a maybe...
If you actually get yours fixed let me know what you solution was/is.
I talked with Bowler Transmissions about it after the initial rebuild. They said they thought they could fix it, but it would require a bore and re-sleeve of whatever area had the original manufacture issue. I didn't want to go thru all that again for a maybe...
If you actually get yours fixed let me know what you solution was/is.
