2005 Sliverado HD Duramax Check Engine Light

[wolfdad]

I read the thread down a bit lower on this subject and would appreciate even some more enlightenment on this issue.

My equipment is as follows:
2005 Silverado 2500HD with 6.6L Duramax Diesel
Edge w/Attitude enhancement
Allison 5 speed transmission with OD
4 inch Flowmaster exhaust
20K Miles on the vehicle
Useage: Pretty much confined to "no-load" street use and occasional pulling of a Pace Toy Hauler to RC Helicopter events.

Scenario:
Yesterday, I was at highway speed (65mph approx., in level III on the Edge) and spotted a merging vehicle. I moved to the fast lane and accelerated (not a punch, but a harder than usual accel). Engine initially bogged, then appeared to cut out and "check engine" light came on steady. I immediately pulled to the emergency lane, check all engine/transmission instrumentation (all were within normal parameters). I then shut the engine off for approximately 30 seconds and restarted. Restart was normal and since all indications were within limits, I elected to drive the balance of the two miles home. During the drive home, the check engine light stayed on steady and it appeared that the transmission would not shift into OD (RPM at 2800 with no shift). On arrival at home, I attempted to back into my drive, but had no reverse (only a flashing cursor under the "R" indicator). At this point, I elected to park it. After approximately an hour, I went back out, got a normal start (other than the check engine light still on steady after an approximate 5 second delay). At this point, I had reverse again.

I am a bit concerned about exactly what happened and why and whether driving the vehicle will do more damage. I had just filled the tank the night before and, in accordance with the owner's manual check the gas cap and reinstalled. In reading the below thread, it is mentioned several times that the transmission was "limped." Is this a common occurance (obviously, my first experience)? I have driven the vehicle ONLY in level III, with the exception of towing, when I dropped it down to level II. Should I be driving in Level I vice III? Last, but not least, is the truck ok and how do I reset the check engine light. With the Edge and Attitude plus the Flowmaster exhaust, I suspect a dealership will NOT honor any warranty.

Any help will be very much and sincerely appreciated.

wolfdad