6 Spd upshift torque reduction

[THEFERMANATOR]

????? - ANY transmission with excessive overlap WILL destroy itself - INCLUDING 4L60E's and 4L80E's. The allison in not special.

So..... a trans can have no "defuel" and live but if it has no "defuel" it won't live. You might want to re-think that statement.
In a diesel engine, fuel IS torque. They are directly linked. To reduce one is to reduce the other. It is a function controlled solely by the ECM and TCM working in unison or the ECM on it's own - the ECM to control max stress on the engine or as RPM/speed control. The TCM requests the ECM to "defuel" to protect the transmission's mechanical limits. Whether the trans is built or not has NOTHING to do with the fact that I have a TCM requesting a reduction in torque from the ECM during light throttle shifts despite the fact that I have removed all visible means of doing so from BOTH the ECM and TCM programming. THAT is the reason I have posted here.

I FULLY understand how the defuel works, and maybe you should try quoting me correctly. I said very clearly that a good tune set up properly would virtually no NOTICEABLE defuel, whereas a tune with NO defuel can destroy one QUICKLY. And 4L60E/4l80E's by design can have overlap without suffering severe consequences in many gears. When you have a trans that shifts by engaging a band, and then a one way roller clutch to safeguard when the next clutch pack comes in, it is inherent that it's design will be more forgiving. ANY direct clutch to clutch transmission does not have this forgivness factor built in. Like I said, it's your trans to do with as you please. But others have tried this and learned an EXPENSIVE lesson. And others would be wise to tread lightly into this area.

As for your question, you must be overlooking a defuel request from somewhere, or it is a table we don't have access to since we only get to see maybe 2-3% of what is actually in the TCM code. And it doesn't have to be the TCM calling for the defuel for it to pull fuel.

[Quinton]

I'm having a problem with the trans tuning also. The stock TCM tune runs fine and shifts fine. But when I go to raise the rpm shift point to 3400, it hangs/defuels. I can't figure out why it's doing it. I will post the Tcm tune and let y'all take a look. I've raised the torque limits/ d5196 table at 3400-3600 to 1000 any ideas?

[Wheelz]

Sounds like the basic engine rev limiter if I had to guess with what info I've got

[Quinton]

It doesn't bounce though like a rev limiter, it gets there just fine the hangs and then shifts. It doesn't set there for long then shifts.

[Wheelz]

It's not a hard limiter. It's a soft limiter so it slowly defuels

[Quinton]

It's not a hard limiter. It's a soft limiter so it slowly defuels

Hmm okay ill check it out ECM tuning then right?

[Wheelz]

Yup. ECM tune. And soft limiters can be set at 3200 but the way they roll fuel off will let the engine run up to 3400-3600 depending on how hard you were in it. I'm not for sure that's what it is, just I'd check that if you haven't changed the rev limiters already.

[Quinton]

Yup. ECM tune. And soft limiters can be set at 3200 but the way they roll fuel off will let the engine run up to 3400-3600 depending on how hard you were in it. I'm not for sure that's what it is, just I'd check that if you haven't changed the rev limiters already.

Alright I will double check that and report back.

[THEFERMANATOR]

Check your max torque VS RPM table in your ECm tune. it is often overlooked and will limit the fuel regardless of what you set the main tables to.

[Quinton]

Check your max torque VS RPM table in your ECm tune. it is often overlooked and will limit the fuel regardless of what you set the main tables to.

I've got it set to 950 all the way to 4000 rpm. Only thing I saw was one limiter not raised. Will try that