shift kit question

[Bowtie boy]

yea lol I have 3.42s.

[2500Ak]

yea lol I have 3.42s.

Ouch that tall I can see how holding gears may be a powerful ally for you.



I was doing some poking around in the EFILive demo, just to see what tables are actually there.

There's a function under corrections labeled

[Manual hold gear 2nd, 1->2 shift speed]

and another labeled

[Manual hold gear 2nd, 2->3 shift speed]

As well as a


[Manual downshift gear, 3->2 shift speed]


Now I'm no tuning expert, not really even a novice I just understand some of the concepts.

But I would be willing to wager if you were to, perhaps change those parameters beyond the parameters you could conceivably generate in a given driving scenario, then perhaps the PCM wouldn't try to override the gearcommand.

What do you guys think?

[Bowtie boy]

I really dont know much about tuning but it sounds like that is what needs to be adjusted. Thxs for the input.

[2500Ak]

4L60E Manual Mode Downshifting 3-2 & 2-1 - EFILive Forum

I think that about solves it.

There seem to be singular speed values that the PCM will not allow the column actuated, manual downshift to occur at.

namely

2-1 Manual 44 MPH {D0928}
2-1 WOT 42 MPH

3-2 Manual 0 MPH {D0933}
3-2 WOT 90 MPH

You said you were at about 40? Lets say that as you punched it, it achieved a little over 40 as it was trying to shift.

It invalidated the parameters, but the gearcommand made it shift anyways. What one might think of as an uncertain shift, not sure whether to follow the manual valves command, or the solenoid.

I was wrong RPM has no barring on it, its based on speed alone.



I'd really like to see the effect of modifying those values to give a gear command like effect, in addition to a gearcommand equipped transmission.


This is still all very hypothetical of course.


Edit:Wait a moment I've got that mixed up. Let me look at this again.

Okay the 40 was addressing the 2-1 shift. So I don't know, it's still worth a try.

The number appears to indicate the speed below which it can shift, which makes little enough sense for the second parameters.

Perhaps the downshift is a mechanical function even without gear command, the solenoid isn't necessary. But that doesn't explain how it waits until the truck is under 62 mph in stock trim...



Or maybe its that it won't immediately hit second at part throttle, and that you must apply WOT to force it to downshift for one reason or another.

I think that might be it, if you put it into 2nd and floor it, it should drop into 2nd.

If you put the selector in 2nd it might wait until you floor it to engage.

So lets say you put it in 2nd, the gearcommand makes it go into second, then it bounces back because the PCM tells (which is shouldn't be able to do but these SK's were made for older transmissions so who knows) it too then it plunges into 2nd when you floor it.

[Bowtie boy]

Thats alot of help. I will definently keep that in mind.

[2500Ak]

D0919 "Manual Hold Gear, 2nd, 2->3 Shift Speeds

D0913 "Manual Hold Gear, 1st, 1->2 Shift Speeds

It would appear those are the designations of the hold speeds, and (D0928, D0933) are the downshift speed entrees. I would venture a guess that this is not just for EFILive, but part of the tuning itself addresses from the code inside the PCM.

I may be wrong though.

[2500Ak]

Seems HP doesn't have these tables, if my other research is correct.

If you get these entries modified in your tune, post up.

If I get my tune before then I'll post up the results as well.