2000 K3500 4L80E... Tow/Haul Mode???

[Tom P]

On the 2001 and newer HD trucks and most of the half tons from '99 and on they gave you a tow/haul mode for the transmission which would increase shift firmness and hold you in a gear longer. This is basically the same tranny that was used in those trucks and should have the capability. Do you have to go with a full blown shift kit to increase shift firmness or can you do it with an ECM tune?

 

[Supercharged111]

Tune alone will firm up shifts. If you 411 swap you can add a tow/haul button too.

 

[Tom P]

Ok I wondered if the 411 swap would open that up.

 

[Supercharged111]

Yes it does, my dually will get just that. I have everything but the time right now.