Transmission/torque converter seems to be shuttering after calibration

[Ryansal]

Hello all.

 

I have a 2018 Silverado 5.3 with approx 22k miles on it., 6 speed trans. 

 

Initially I got a few mods, borla dual exhaust, Afe gt cold air intake, swapped the throttle body and intake manifold for the L86.

 

After this point was running much stronger but lacking in areas. 

 

I decided to get the long tube american racing 1-3/4" long tube headers, 3" y pipe with high flow cats, 160 degree thermostat, brisk performance spark plugs. 

 

And finally it was calibrated/tuned, really woke her up***

 

As of just today,  the transmission?? seems to be shuttering (for lack of a better word) at highway speeds, and not as drastically upon acceleration and constant speeds.

 

Any advice as to what this may mean, how to fix it is greatly appreciated!  Thanks in advance!

[CamGTP]

I would probably want the truck on a scan tool to watch a few of the transmission parameters related to the torque converter. If there is a lot of slip, then you do have a problem.

 

When I tune the transmission I remove it's ability to lock the converter is gears 1-4 to extend the life of the converter and I change the lock up settings for mph and allowed slip.

 

Torque converter failures are a known issue with the 6 speeds.

[Ryansal]

Thank you!

[pokismoki]

there is also a section where tuners remove slip from the lock up table.  i set the v4 mode tcc lock up to zero slip and I got horrible vibrations, went back to stock settings on slip for TCC v4 mode and all smoothed out again. but i zeroed slips on all lock up points in 4,5,6th until it hits V4

 

some tuners might get aggressive in tunes and most tuners are still learning, which makes them dangerous IMO

 

with all that power adders i would assume the tuner deleted the v4 , but I would log your tcc, see what changes where made, use the compare file tool in the software

Edited October 11, 2021 by pokismoki

[Grumpy Bear]

47 minutes ago, pokismoki said:

there is also a section where tuners remove slip from the lock up table.  i set the v4 mode tcc lock up to zero slip and I got horrible vibrations, went back to stock settings on slip for TCC v4 mode and all smoothed out again. but i zeroed slips on all lock up points in 4,5,6th until it hits V4

 

some tuners might get aggressive in tunes and most tuners are still learning, which makes them dangerous IMO

 

with all that power adders i would assume the tuner deleted the v4 , but I would log your tcc, see what changes where made, use the compare file tool in the software

 

^^^^^

[Ryansal]

Sorry I meant to say it's slipping at points, not shuddering, and pretty much only in 5th and 6th gear at lower RPM.

 

I was on the highway (maybe 65 mph) at say 1500 to 2000 RPM and had so many point of sudden "slips" for lack of a better term, and had to exit the highway.

 

in gears 1-4 it seems to have no real issues, even at high rpms, and gears 5 to 6 has seemingly no real issues at high rpms for the most part.

 

But when the RPM goes down to say 1500 to 2000 at at a constant speed ( 40mph to 60Mph )  it seems to have the worst points of slippage

 

 

[newdude]

5 minutes ago, Ryansal said:

Sorry I meant to say it's slipping at points, not shuddering, and pretty much only in 5th and 6th gear at lower RPM.

 

I was on the highway (maybe 65 mph) at say 1500 to 2000 RPM and had so many point of sudden "slips" for lack of a better term, and had to exit the highway.

 

in gears 1-4 it seems to have no real issues, even at high rpms, and gears 5 to 6 has seemingly no real issues at high rpms for the most part.

 

But when the RPM goes down to say 1500 to 2000 at at a constant speed ( 40mph to 60Mph )  it seems to have the worst points of slippage

 

 

 

 

 

I'd get a scanner that can read TCC slip.  Monitor it during this scenario.  Anything over 0-20rpm slip during a steady speed is either a minor or major problem depending on how much slip is happening.  

Edited October 13, 2021 by newdude

[Ryansal]

I appreciate it

[Ryansal]

Considering this seems like a calibration issue with the transmission (as it was "on the road" calibrated) is it possible for this to happen sometimes, and then at other times nothing happens at all?

 

Case in point, I drove it this afternoon at around 25-30 MPH at 1000-2000 RPM in 5th gear and felt the several small  "shifts" or "slips" that I normally feel. 

 

However, when back on the highway, 65 MPH at around the same RPM 1000-2000, and didn't feel any of the many slips, jerks, I felt just this past saturday at the same speed and RPM's.  

 

Is this commonplace with a "modification" like this?  Thank you!

[M1ck3y]

Entirely possible your tuner knows what he's doing and the transmission is doing some learning. 

Edited October 14, 2021 by M1ck3y

[Ryansal]

Thank you!