600 rpm slip limit solved!!!! OS 25941752

[THEFERMANATOR]

I have an AL5(01 DURAMAX/ALLISON combo). If I drop back to my tow tune I get lockup in 2nd no problem, but my big tune with a hot trans and I don't get lockup until the 3-4 shift(makes for a NASTY 3-4 shift). The whole reason for people wanting these tables is because under big power you don't get lockup without a lockup controller.

[beav]

I have an AL5(01 DURAMAX/ALLISON combo). If I drop back to my tow tune I get lockup in 2nd no problem, but my big tune with a hot trans and I don't get lockup until the 3-4 shift(makes for a NASTY 3-4 shift). The whole reason for people wanting these tables is because under big power you don't get lockup without a lockup controller.

In your "tow tune" are you in T/H mode? I'm assuming so. I'm getting lockup in the upper range of 2nd whether T/H is enabled or not. Actually, when not in T/H I get about 60% TCCDC right after going into 2nd and about 75% through the 2nd gear range (before shifting to 3rd,) I get 97.6% TCCDC and ~0 slip. Maybe it is just the massive Cummins torque that allows it to hit 625 RPM slip so quickly.

I looked at a few logs and they were similar, but when I get a chance, I'll log it again. I do not have any lockup controllers, just EFI tuning.

[Chavez91]

If you're getting lock-up in second gear, you're not throwing enough power through it. lol

On my maxeffort tune Im super lucky if i get lockup on the 4th gear shift. But most of the time i dont get lock up till im at the top of 4th. T/H or normal mode.

Its a hit or miss thing.. but would be nice if it could be made more consistant. As in Lockup in 2nd every time and I could get rid of my lockup controller.

[The Alchemist]

Hi guys, could someone please explain to me ( and others reading this) what is this slip and WHY is it important in a manner we can all understand...thanks, Mike.

[beav]

Hi guys, could someone please explain to me ( and others reading this) what is this slip and WHY is it important in a manner we can all understand...thanks, Mike.

The "slip" that everyone is referring to is the 625 rpm minimum difference between engine speed and tranny input shaft speed that must be achieved before the T/C can lock. It appeared that no matter what you did to your tune, until you achieved this "slip" (~625 rpm) you would not be able to lock. It wasn't until the gracious OP and others that he acknowledged broke into the low-level code and found the info needed to override (or change) this slip limit.

Soon, we will be able to make that value reasonably whatever we want it to be. Hope that makes sense and if I have stated this incorrectly, someone feel free to correct me.

[beav]

If you're getting lock-up in second gear, you're not throwing enough power through it...

If I am able to power through this converter at lock-up, then I'll be asking for a $1,300 refund. When it locks, you know it! I was just having a little D-max/Cummins fun with my comment. ;-) If you meant something else, then please enlighten me as I am confused.

[beav]

I have an AL5(01 DURAMAX/ALLISON combo). If I drop back to my tow tune I get lockup in 2nd no problem, but my big tune with a hot trans and I don't get lockup until the 3-4 shift(makes for a NASTY 3-4 shift). The whole reason for people wanting these tables is because under big power you don't get lockup without a lockup controller.

Here is a log that I made today and it is with a tune that should be producing 500-550hp. It is from a roll in 1st. The trans was not quite what I would consider "hot", but my other logs do the same with a hot trans. Hopefully this may reveal something. One thing I do not understand is why there is such a separation between the commanded gear and actual gear positions. Is this normal?

[tradin1]

i have never tried to tune anything myself with efi, so who would be the best person to walk me through what to do, or where can i have it done. obviously this is not your typical Duramax/Allison combo, so is there someone that has some experience with cummins/allison tuning? it shift fine other than these two complaints.

i have a cummins VP44 engine (450hp) with an A40 allison 6spd that the tcc does not lock up till 4th and unlocks on part throttle just like you are talking about fixing.

thx

[JoshH]

April has come and gone. I have been looking for a new update, but I haven't seen it yet. Did I miss it, or is it still being tested/finalized?

[vortecfcar]

It's in beta. It works.