Well, my car started acting funny today. Cruising along at highway-speeds, it felt like sometimes the lockup wasn't engaged...

Got out the scanner, and sure enough, a push of the gas pedal reveals 600+rpm of slip _with_ the TCC engaged. It comes and goes though, so it's not completely busted at least..

Anyhow, this is RPMs triple-disc converter, so it should hold up for a lot more than my 360RWHP. However, I think I made a mistake when doing my trans tune, and was hoping some of you guys could give me some input on if what I did was the cause of the failure.

I tuned it so that at 0% throttle, the lockup would still stay engaged. I did it because I like to engine-brake when going down-hill (driving stick for too long I guess), but now that I think of it, it probably puts a lot of stress on the clutches in the torque converter.

So, could that be the cause, or should I continue looking?

 

Can your scanner command lockup? Command lockup from like 30 on the highway up till when it starts slipping. If its stays locked at lower speeds when commanded chances are your 3/4 clutches are burned up or 2/4 band

 

Yes it would put more strain holding a load and at min line presure.

 

Huh? The torque-converter is slipping, not the transmission.

 

Enough to fry a triple-disc lockup after a few months of DDing ?

 

Your converter wont lock right or usually WONT at all on the highway if your 3/4 clutches are smoked or a band or both. In my case when I kept loosing 3/4 clutches and 2/4 bands due to the manual valve not adjusted right bleeding pressure off I kept loosing lockup and OD on the highway. My converter would lock fine if I commanded it to early then once it got to highway speeds it would slip like crazy due to the 3/4 clutch burned or 2/4 band. You could also be getting some misfires. I dont know what you have your misfire detection set to in your tune. If you know someone with hp tuners or efi live they can change it

 

I've got HP Tuners, and the misfire detection is not an issue. It's been tuned for the stall, and I logged it yesterday as well to see if that issue crept up on me again, but no dice.

I'm getting slip between the engine RPM and the transmission input shaft RPM, which leads me to believe it's the torque-converter, and not the transmission itself, but I might be wrong here..

 

Thats how it comes from the factory. I don't see many people burning up stock converters because of this.

Whats done to the tcc duty cycle tables? As per Performabuilts sticky thread the min and max tcc duty cycles should be set to max to avoid tcc problems when not using a shift kit or modifications to the trans. Got a shift kit or PWM elimination?

I attached my stock tcc apply release table and the modified one. I still keep it locked up at 0% not an issue in over four years.