lly 5spd to 6spd conversion tuning

[protrac]

wondering if anyone has dabbled in tuning the trans to get that double overdrive that they have in the lbz?
i know that duramax tuner has a kit but you have to buy their valvebody and tcm together for 2k. I run a transmission shop and don't see why we can't just tune the TCM for the added ratio?

[goodlifegearhead]

I am curious about this also

[mulli6971]

I just got a 2005 Sierra 2500HD LLY and was wondering the same thing. Following.

[HpTunesandmore]

following I see the 5-6 speed parameters in lly tune. I wonder if we change the valve body with the extra solenoid and change the values it would work?

[Lennydmaxguy]

I'm interested in finding out as well. I have a 2005 that already has the conversion kit and a working 6 speed tune, but I can't access the 6th gear tables in Efilive, so this is exciting. I'll post my read, and if someone wants to try it on a stock transmission and see what happens, that would be great. It does have a few tweaks for my specific truck, but it should work overall.


Len AL5 6spd Custom.hpt

[Lennydmaxguy]

I confirmed today that the 2004 and newer Allisons had a G Solenoid, so in theory you shouldn't need to do any internal work, if I understand correctly.

[TheRedMonkey98]

just wondering what came of this. if anyone has tried it and if it works

[jeallen76]

I've installed the 6spd kit from Duramaxtuner.com. They are using a VB from 17-19 allison 24295617 and a preprogrammed replacement tcm 29537441. I bought HP to try to tweak some of the shift parameters but HP won't read the tcm. I like it but the 3rd shift above 60% TPS is harsh, like the shift happens on the ramp up from defuel.

[Lennydmaxguy]

Yeah, they lock their tcm, so you'll need to work through them for a tune revision. Or you can do what I did and get an unlocked tcm. I got mine from ecmcustoms.

[76Comet]

no extra wiring was required?