on 4-5 shift, RPM's increase

[Spartus]

I've recently noticed on my newly aquired 2009 Silverado that during normal street driving on my 4-5 shift, there is a delay, then rpms increase 200 rpm before the shift completes and rpm's drop down. Is this what you guys call shift flare? This is happening on BOTH my stock tune and a tune I purchased. On my purchased tune the pressures had been increased by 60 psi across the board and it shifts the same as the stock tune. Stock tune is posted below. Maybe someone can tell me if I need to increase/decrease pressures in maybe the apply/release for the 4-5 shift.. Or maybe this is NORMAL? Thank you.

[Mister Peebody]

It does sound like a flare to me and from what I've gathered, flares are almost always mechanical.

[Spartus]

Thanks for the reply. I've been searching through old threads for ideas, but everyone seems to have different ideas on how to fix this. I've seen ideas from Raise Max pressure, lower shift time, to change shift final normal, to shift time torque adder. I'd prefer not to smoke my clutches.

[Longslyde]

First, is the engine tune stock? If so, load the stock trans tune back into the tcm, then go to your scanner and reset all transmission adapts, Apply trans preset, then perform a fast learn. If you have not done this before, refer to the post in the sticky. If it is not mechanical, this should resolve it. Definitely clean the mass air flow sensor if you haven't yet. it sounds like the Delivered Torque reading may be off. That is primarily read from the MAF and can do exactly what you are describing. Maf can get dirty especially if a K&N oiled air filter has been used. Good luck!

[Spartus]

Thanks for the reply. I first noticed the flare on a tune I paid for. So I reloaded the stock tune and the flare was still there. However, after the trans went through the learning process, the flare is now gone and the trans shifts properly. I will have to look at the changes made to the 4-5 shift in the paid tune and maybe put the shift times back to stock or adjust the changes to 25% instead of 50% and see if that helps.

BTW, this is a stock truck, stock air filter with 62k on the clock. Yes, the MAF probably needs to be cleaned anyhow. When I cleaned the MAF on my 2005 Tahoe it turned into a beast. I usually use electrical contact cleaner and a Q-tip.

[planethax]

Use the compare tool to see changes.
Post both the stock file and new file here and we can take a look as well.

[Spartus]

Ok, here is my base tune, and tuned file.

Keep in mind, the 4-5 flare is only with the TuNED file.

Thank you.

[Russ K]

Try multiplying the 4-5 Shift Time Torque Adder Upshift tables by .75 at a time.

Russ Kemp

[Spartus]

Russ, that is what I was planning on doing. I re-loaded the tune yesterday and will give it a few days to learn then post back. I had a dealer appointment Friday, so I've been running stock tune for the last week.

[mickycochran]

I've recently noticed on my newly aquired 2009 Silverado that during normal street driving on my 4-5 shift, there is a delay, then rpms increase 200 rpm before the shift completes and rpm's drop down. Is this what you guys call shift flare? This is happening on BOTH my stock tune and a tune I purchased. On my purchased tune the pressures had been increased by 60 psi across the board and it shifts the same as the stock tune. Stock tune is posted below. Maybe someone can tell me if I need to increase/decrease pressures in maybe the apply/release for the 4-5 shift.. Or maybe this is NORMAL? Thank you.

[Spartus]

Russ, that appears to have fixed it. Thanks for confirming my thoughts.