d2903 factory set at 10?

[Ritch]

I have a 99 5.3 truck and the factory set d2903 (minimum TCC PWM) is set to 10. From what I have read this should be way higher, like 75-90. Maybe this is an OS issue?

Also, you might notice base pressures are set low. I have adjusted because the shifts were too hard after Trans-Go shift-kit. Maybe there easy an easier way, but it helped alot.

[joecar]

Hi Ritch,

You only need to bump up D2903 if the TCC is not being locked all the way... i.e. if you find TCCDC stuck below 90% for more than 5-10 seconds at a time... if you see that happening then set it to 90 (but make sure that it is lower than D2904).

The shift kit physically increases the apply rate (increased line pressure, increased flow to apply component)...

The three things that you can use to reduce the level of hard:
- reduce shift pressure tables (like you did),
- increase shift time tables (but maybe leave these at zero with the shift kit),
- increase shift torque reduction tables (you already have this).

If you're getting a hard shift at low throttle, then increase the low end of the TR tables.

After reducing the shift pressure tables, how different is the shift feel...?
Does each shift still give a positive/definite feel (across the throttle range)...?

[Ritch]

Thanks! The truck is not back on the road yet. The snow has finally gone and the streets are are being swept. I will may try the shift time factor. The kit increased accumulator pressure significantly too, making the 1-2 shift a real chirper.

[Ritch]

TCC seems to be slipping a bit while cruising up hill. TCCSLIP shows this in the attatched file. You are saying increasing D2903 should illiminate this?

BTW shifts feel good. Easily felt. The torque convertor is now a 3200 from 2500, I think that helped soften things too.

[joecar]

What is TCCDC when it is slipping...?

If the TCCDC is not above 90% when you detect slipping, then trying setting D2903 higher (but make sure you keep the relationship D2903 < D2904 for the same cells).

[joecar]

In your log, when TCCMODE=Lock, the most amount of TCCSLIP is 95 rpm... is that what you mean...? In this area the TCCDC is 30-40%...

I then see the TCCDC go to to 58% and TCCSLIP goes down to 2 rpm.

Try bumping up D2903 and see what happens.

[Ritch]

TCCDC seems to be about 35% and TCCSLIP peeked at 70rpm while TCCmode is LOCK

D2905 was set from factory to be 0 when TCCslip is 0. I will change that aswell.

[joecar]

Note that TCCSLIP is valid only when TCCMODE = Lock.

[joecar]

Those ripples are strange...

It looks like the PCM lowered TCCDC until those TCCSLIP ripples occurred...

I can't tell if the PCM is performing a test (why else would the PCM command a ripple in TCCDC) or what.

Those ripples also show up on the RPM waveform...
I don't think it is due to misfire...
if you're running with a MAF then also log MFTOTAL and MAF...

you can get rid of some pids like these:
- PRND
- PRNDSW-xxxxx
- SHIFT32
- SHIFTxx
- SHIFTxxERR
- TFMCUR
- TFMDES
- TFMDC
- TSHIFT
- TURBINE
- TSTATE01

Keep TSTATE00 and the remaining pids.

Interesting log, thanks.

[joecar]

The tun file in post #7 shows D2903 to be at 75% or higher in all cells... so look at D2901 (zero)... try setting that higher and see what happens.