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2003 mack E7 and allison auto

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We just purchased a 2003 Mack with a 350hp E7 and a 5 speed allison auto with almost 500k miles and over 22k hours on the truck. We know nothing about the history on the engine and tranny.  What should we look at first or possibly replace? The trans fluid looks nice and clean and clear, it definately needs the motor oil/filter changed as it's nice and black.  I already scared myself and was kinda reading through some posts about the E7 and EGR issues.  How do I know if this engine has an EGR or not?

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I also noticed driving it home after purchasing it  that when pulling hills, then sometimes when you put the pedal down to pull the hill then the turbo spools up but then sometimes after 5 seconds or so then it will spool up even more and it has quite a bit more pulling power even though the tach doesn't move (it's not downshifting). It does it with the cruise on and also with it off so i don't see how it could be the pedal sensor. Could this be what they call a dual HP engine? Why would it be doing this? It didn't do it on every hill, sometimes it had the extra power immediately but other times it was delayed.

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Should be a non egr engine! 2004  was the anniversary Of EGR   Celebrated  daily/ weekly / monthly/ yearly at a shop near you! 😣

I would have your fuel pressure checked Also if it has a waste gated turbo it may be sticking  !

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  • 1 month later...

no one knows the torque rating on this engine at 350hp?  Also, any other ideas as to why sometimes when pulling then the truck is only running at like 1/2 throttle and then all of a sudden sometimes after 3 seconds other times after 30 seconds or so, then it will all of a sudden start pulling like it should at full throttle? it does the same thing on and off of cruise control.  Also, I dont know if it's normal or not with an E7 but when taking off from a complete stop then there's a few second lag where it doesn't seem to want to hardly pull or spool the turbo. Is this some sort of emission or smog setting to prevent smoke at first pull off?  It really sucks when loaded down and starting off cuz it doesn't want to immediately get out of the way and clear the intersection and then after the rpm's get up then it pulls good and hard.

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On 8/20/2018 at 8:22 PM, niceguypmp3 said:

I am also curious as to what the Torque rating would be on this 350hp E7?

1360 lbs. of torque @ 1200 /1250 rpm.

Edited by 41chevy


 “Life’s journey is not to arrive at the grave safely, in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘Holy shit, what a ride!’


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  • 3 months later...

Hey we both have the same issue, sometimes my 04/300/Allison does the exact same thing! Sometimes from a dead stop, almost instant boost, good power...sometimes normal power, then sometimes won’t build good boost through first/second maybe into third before you hear the motor pitch deepen(more fuel)followed by rise in boost and normal power. 

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