A few qyestions that were beyond my dealer:
1. Looking for more detail on the DOD engine. Is this a simple fuel shutoff or complex valve switching?
2. What all happens with trailer mode ? (shift patterns, autoride, throttle??)
3. How are the 20 inch wheel/tires in the snow?

Thanks.

 

i can anser #2 if its like the tow haul mode all it does is tell the computer to change the shift points around to make them a bit harder so that when your towing somthing the tranny isnt taking as long changing gears and the tranny isent getting as hot.

 

ok
#1 the dod goes in effect when the engine if warmed up
when the engine is under a certain amount of load and above i think 25mph it shuts off 4 cyls, but for no longer than 9minutes and then it has to turn the 4 cyls on for a minute to burn off any deposits.

When dod is active, you fuel injectors get shut off, also - there are 4 solenoids under the intake "under the valey pan"
this engine has special oil passages
when the solenoids are actuated, they allow the oil to pressurize a plate inside the lifters which allows the inside of the lifter to free float while the outside still moves with the cam.. this shuts off the valves "intake and exhaust"
they do this so that when the engine is in dod mode, you're not throwing extra oxygen to the convertors which would burn them out..

#2 ok.. um.. first off, when you touch the turn signal lever, it blinks the light 6 times instead of the usual 3
yeah you have a stronger shift to keep the clutches from terring apart prematurly
also if you look at the horse power and torque rating, it tells you the rpms the engine achives these stats
so when your're shifting and the pcm sees that you have a high torque request, it tries to keep the rpms around that range to provide the most possible power to the trany. although this depands on what the torque request signal is

#3 well it all sepands on how the tires are, the bridgestones seem to be pretty good, and no qorries because gm's stabilitrac rules, yeah it was better on my 05 avalanche because i had a posi in the back and not a locker like my 07 tahoe has, although it still does a great job keeping you in control even when in 2wd