GM's 2006 model-year Pickup Trucks

[More Power]

Two Thousand Six
GM's 2006 model-year Pickup Trucks

The 2006 model-year Chevy & GMC diesel pickups began arriving on dealer lots in August of this year. While not much has been added or changed to the pickup styling or option list, the big news is the new RPO code LBZ Duramax 6600 diesel engine. Go here for a look at the new trucks and to learn more about the new uprated Duramax diesel engine.

[BillMoncrief]

Hello;
Jim did you happen to measure outside to outside with the mirrors extended? My powervision mirrors just don't go far enough to suit me.
Thanks
TOWERJAKE

[Rollingon]

More Power - Regarding the tach photo and the deletion of the shaded red zone.

I'm still confused on operating in the shaded red. My 2002 Owners Manual (pg 2-97) says, and I'm quoting, "Don't operate the engine with the tachometer in the shaded red area". Since it won't go up there under power, then they've got to be talking about compression.

Is the Owners Manual wrong? Is the 2006 engine that much different? Or what? What's the background or source for the "mistakenly thought" statement?

[More Power]

No I didn't measure the mirror outside edge to outside edge.... Should have... Hindsight....

Redlines - I doubt that those who write and edit owner's manuals are all that familiar with these engines or drivetrains. You are correct in saying the engine won't go above 3200 when under power. This, in part, makes the dashed reline redundant, which explains why they eliminated it. Likewise, the powertrain programming won't allow the engine to run above 4800 while in grade-braking (unless you've got a manual trans or the new 6-speed Allison will allow the driver to override the grade-braking rev limits).

I have received quite a few email messages since late 2000 about redline confusion. Here's a recent email exchange where a Duramax owner expressed concern about rpm redlines.

Jim
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Date: 08/21/05 13:04:21
To: ontheroad
Subject: Re: tach redline
At 10:47 AM 8/21/05 -0700, you wrote:
I see your page and thought may be you could help me. I have an 03 Duramax with the Allison trans. When it is in the tow haul mode and towing my trailer going down hill, it starts downshifting. I think that it drops into what I think is 3rd too soon, and then it red lines the tach to about 32 or 33 hundred. Is that normal and how do I keep it from doing this?

Thanks Earl

My reply:

Hi Earl,

There are actually two redlines indicated on the tachometer. The dashed red beginning at 3200 is for when under power, and the solid red beginning at 4800 rpm when grade-braking.

The 2006 trucks now have just a single redline beginning at 4800, to help reduce the confusion about redlines.

Jim

Earl's followup message:

Thanks Jim so what you are telling me is that the dashed red line is not an indication that the engine is in the danger zone.

Takes a load off my mind. Though for the old school types like me redline means danger back off.

Thanks Earl
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[ 08-24-2005, 02:13 PM: Message edited by: More Power ]

[MIKE MOG]

I can understand the redline for grade braking being in the solid red and causing a over rev and throwing a rod or whatever. BUT I dont under stand the dotted red line for power IE, anyway you look at it to many revs should blow the engine at least thats the way it is in the gas engine. Why is a diesel different?
Mike

[DmaxMaverick]

Originally posted by MIKE MOG:
I can understand the redline for grade braking being in the solid red and causing a over rev and throwing a rod or whatever. BUT I dont under stand the dotted red line for power IE, anyway you look at it to many revs should blow the engine at least thats the way it is in the gas engine. Why is a diesel different?
Mike

On the trucks that had them, the red area on the tach can't be reached under power. The shaded area shows the acceptible range for compression. In any case, the PCM won't let the engine reach an RPM that could damage the engine. I'm sure there is a way to do it, but certainly not under any "normal" circumstances.

Diesel engines have a lower redline than gassers due to rotational mass. The larger they are, the lower it is. Some engines have a redline in the 100 RPM range, but you'll never see one in a pickup.