Allison 6sp: TCM Dyno tune

[x MadMAX DIESEL]

Well I made this tune hoping to stay in 4th gear. The problem is it still down shifts to 3rd at WOT? Could it have something to do with a temperature limit table or something of that nature?



View attachment TCM dyno tune.zip

 

[1chevy02]

I'm gonna try the same thing on the dyno next time. I don't know to much about trans tunes but it look to me like you need to raise table D5028 also to prevent the 4-5 upshift

 

[x MadMAX DIESEL]

Correct, it should go into 4th at 14mph and stay there till 80. It should only down shift if Im at 10mph or slower, but it still does

 

[1chevy02]

have you tried messing with table D5028 to set the rpms up also

 

[wdino73]

I know it's hard to do when not on a dyno, but may you can do a data log on the street, just trying to help, Good Luck

 

[x MadMAX DIESEL]

have you tried messing with table D5028 to set the rpms up also

No, that is only for the upshift. I have problems with it downshifting

 

[1chevy02]

ok sorry i guess i misunderstood i had problems with mine still upshifting. what about holding it in gear with the dvt on the scantool

 

[x MadMAX DIESEL]

Ive thought of that but I figured this would be easier. If you noticed the trans operates normally in O/D. turning on tow haul should make the truck go into 4 at about 15 and stay there. Should be easy just tell the dyno operator to hit t/h and he wont have to worry about it shifting

 

[x MadMAX DIESEL]

anybody else have any insight?

 

[SteveFord]

From what i understood is that on the 6 speeds you can only stop it from up shifting not down shifting. I think you'll have to find a good rpm starting point and roll into the throttle just hard enough to keep it from down shifting during a dyno run.

 

[JoshH]

Are you leaving it in D or pulling it down into M? If you put it in manual mode, the TCM shift point changes will not work. If that isn't your problem, try changing all except Pattern A. I had a problem with an LB7 doing the same thing.

 

[JoshH]

From what i understood is that on the 6 speeds you can only stop it from up shifting not down shifting. I think you'll have to find a good rpm starting point and roll into the throttle just hard enough to keep it from down shifting during a dyno run.

I did it on mine.

edit: I just went and looked at my tune. I have it set to hold 5th in normal mode, and shift through all the gears like normal in T/H mode.

 

[x MadMAX DIESEL]

It in O/D.

 

[x MadMAX DIESEL]

I'll try pasting into those patterns too. I just rememberd that my truck pops out of gear when using the DVT to lock it so I hope this will keep it from downshifting. Could be my only way to lock it in gear

 

[1chevy02]

did you ever get this figured out?

 

[x MadMAX DIESEL]

Nahh I haven't messed with it since. I've been busy

 

[GTA23109a]

I've been thinking about this same thing for a while. I threw what I *think* should be a 4th-gear-hold dyno TCM tune. If somebody wants to take a look at this and see if I'm even on the right track, that'd be great.

 

[Antsdmax]

sorry to bump this thread up but will the above tune work for a 4th gear dyno hold?

 

[c20elephant]

sorry to bump this thread up but will the above tune work for a 4th gear dyno hold?

Don't know why would you need it, just drop the shifter into M-mode and click to 4th, works in regular and T/H mode on the 2006-2010 trucks. And honestly, I would NOT use a tune that was not read out of my trucks TCM...

 

[N2BRK]

I didn't look at the tune, but I have to disagree, Mike. My truck kept downshifting when Mark was trying to work on the bottom part of my tune while on the dyno. It would have been a big help to have a tune that forced it to stay in 4th.