tcc problems

[danny68ss]

tcc locks under acceleration and un locks while driving at steady speed any ideas im running a 05 5.3 with stock transmission in a 2000 s10

[joecar]

tcc locks under acceleration and un locks while driving at steady speed any ideas im running a 05 5.3 with stock transmission in a 2000 s10
Does it stay locked, or does it go from unlocked to locked...?

How much throttle are you applying when you notice this...?

Your D1005 (TCC Release Speeds 3rd Gear) is fairly shallow, you need a lot of throttle to get an unlock.



Also, at steady speed, are you getting any misfires...? Does your ABS tell the PCM if there's "rough road"...?

[joecar]

Log files...

[danny68ss]

What pids do you want logged i just logged for the lockup yesterday it shows its locked but its not but when i accelerate it locks but when i go back to steady driving it unlocks but shows its locked i might have a transmission problem im going to drop the pan and check the scelonid

[joecar]

Log these pids:
SAE.VSS
SAE.TP
SAE.RPM
GM.KR
GM.MFTOTAL
GM.TFT
GM.GEAR
GM.TFMPRS
GM.TCCSLIP
GM.TCCDC
GM.TCCMODE
GM.TSTATE00/03/09/10/12

[danny68ss]

Solenoid didn't help, still just locks up under acceleration.

[Taz]

tcc locks under acceleration and un locks while driving at steady speed any ideas im running a 05 5.3 with stock transmission in a 2000 s10

You should add GM.GEAR (as Joecar suggested) and GM.TSHIFT to your logged PIDs. This would tell us what gear the transmission is in, and what shift mode is being used (i.e. Tow / Haul vs Normal).

I reviewed your log, and it certainly seems like the TC is following the apply / release speeds that you have programmed - difficult to be exact about this without the GM.GEAR PID. With respect to the TC being locked, it doesn't matter if you are accelerating or not, what does matter is the TPS % versus the vehicle speed per gear. Most of your log is at less than 30% TPS - even at speeds over 50 MPH. During cruising conditions the TC is locked, but unlocks when the throttle closes (a brief coasting situation) - which is normal for truck tunes.

Also, in Performance Mode (Tow / Haul) you have significantly lowered the TC apply / release speeds, as compared to an OEM tune. If that log was in Tow / Haul Mode, then the TC would have been locked earlier than normally occurs.

Try another log with the additional PIDs added. At this point it looks like the transmission and TC are OK, and are following the programming in the tune.

[danny68ss]

it gains rpm when I lift is the reason im thinking its locked while on the gas and unlocks under steady throttle you thinking it needs to be set to lock with less throttle

[Taz]

Thank you for posting the additional logs - these were very helpful.



it gains rpm when I lift is the reason im thinking its locked while on the gas and unlocks under steady throttle you thinking it needs to be set to lock with less throttle

No, that is not what I meant. I simply meant that the transmission, and thereby the TC, appear to be following the parameters as configured in the tune - the inference being that there is no indication of a mechanical or electrical problem with the transmission.

How it shifts, and when the TC is locked / unlocked is mostly at your discretion as the tuner.

[danny68ss]

Ok thanks for looking i may be hearing something else i just noticed the rpm jump when i back off the throttle thought it was unlocking the converter

[Taz]

Ok thanks for looking i may be hearing something else i just noticed the rpm jump when i back off the throttle thought it was unlocking the converter

Yes sir, it is unlocking the TC when you release the throttle - that is what truck tunes do. If you review your logs, when you ease up on the throttle, you will see the TCC status go from "Locked" to "Coast" (which means that it is getting ready to unlock), then to "Off".

[danny68ss]

Does the torque converter slippage look normal for being locked

[joecar]

BTW: TSTATE09 and TSTATE10 are particularly useful because they show the reason the TCC is unlocked.

[danny68ss]

Is that amount of slippage normal while locked

[joecar]

That's ok and is normal.

[danny68ss]

Ok i added the other pids and what im hearing is when it go to full lock it only does it at around 30% throttle anyway of adjusting that