I was looking at the allison website and they said that a downshift could occur causing the rpm to go to 4000 and if it reached 4800 it would upshift. This stated it was for the LB7 diesel. I was thinking the the rev limit was 3250. Does anyone have the answer?


Kirk

It will only provide fuel until 3250. But it will run free up to 4800. You will see 2 different redlines on the duramax. One shaded up to a certain point an solid red at another point. I'm not sure the exact #'s but I would guess the solid red will start at 4800.

It was discussed here http://dieselplace.com/forum/forum_posts.asp?TID=5711

Thank you Max for the reply. My tach does not show any color, but I get what you are saying. I am glad that I found this out now, next month I will be in the mountains towing my fifth wheel camper and it may very well rev that high desending grades.


Thanks Again


Kirk

I just looked and I stand corrected. It does show exactly as you said with the red after 3250


Kirk

Why does a diesel have a lower redline than a gas truck exactly? If you punch a diesel to the redline does it run up and shift right when it starts at the shaded part? My Z71 screams to the shaded redline if I punch there. Can a stock diesel keep up with and or have as much acceleration as maybe a 6.0 of the same size. Everyday day I get closer and closer to wanting a Duramax but I still don't know if a diesel has the same driving mannerisms as a gas vehicle.

Yes a duramax will run with a 6.0L in the same size truck. Yes it will shift at 3250 rpm (shaded part) It doesn't need to rev to make power. There is almost nothing to be gained by running it any higher. You won't even notice that you don't have the revs because it will pull like a freight train at any rpm. Trust me, you are not going to ever go back to a gas truck.

I know where your coming from. When you hear your gasser revving at 5500rpm you are thinking, man that thing sounds mean and powerful. One you own a diesel and drive it a bit you will realize how much of a noise maker your gas truck was and little else.


As far as 'mannerisms' the main thing you will notice is that it doesn't shift down as often as a gas truck. On your gas truck you step on it at 30mph and it will shift down 3 gears into 1st, make a bunch of noise and it gives you the illusion that you are accelerating fast. In a diesel you might not shift down at all depending what gear it is in, it will speed up but you won't think it is speeding up as fast because the sound barely changes. But put them side by side and it tells a different story.


A good buddy of mine had a 98 Chev with a 5.7L. When I first got my truck he wanted to go for a ride. He wasn't impressed. His comment was that his truck would 'blow the doors off' of my truck. He understands the advantages of diesel and he was also considering buying one at the time he just felt that the diesel wouldn't be as drivable as his gas 1/2 ton. We then went for a ride in his truck. We were cruising through town at about 30mph and when traffic cleared up he punched it. It shifted down to first and took off. His comment was 'hear that, thats power'. That of course brought on a race. My truck was completely stock at the time. To his surprise he couldn't keep up with my duramax at all. No matter what he did he was always a few good lengths behind. To make a long story short, he now drives a duramax and also sings the praise of diesel.

Thank's Max Power. That's just what I was looking for.http://www.dieselplace.com/forum/smileys/Big Smile.gif I am sort of hearing the sound and not the ( throw you back in the seat without the noise power). My neighbor says mine sounds like an airplane because the dual 5". I sounds like a 454 at idle though, I like it. I just wish I could hear some Dmax roaring by all the time to turn heads.http://www.dieselplace.com/forum/smileys/Thumbs Up.gif