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Cummins 425 HP and Allison 3000? (For Pete 892)

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  • Cummins 425 HP and Allison 3000? (For Pete 892)

    No hijack intended but I can't seem to post a new thread.

    I just read preliminary specs on a new truck. They call for a Cummins 425 HP engine with an Allison 3000 transmission. I, somehow, thought that this engine required a 4000 transmission. Any thoughts out there.

    Posted for Pete892
    Originally posted by ThNozzleMan
    Why? Because we are firemen. We are decent human beings. We would be compelled by the overwhelming impulse to save an innocent child from a tragic, painful death because in the end, we are MEN.

    I A C O J

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  • #2
    My thanks to 343

    I don't know why I can't post new threads, but can post replys.

    Thanks much for your help.

    Stay safe,

    Pete Sinclair
    Hartford, MI
    IACOJ (Retired Division)


    • #3
      425 and 3000

      The 425hp isl is the same engine as the 400hp reworked with 2007 emmisions. The 3000 is still the trans on this series of motor.

      The 430hp and larger require the 4000.

      stay safe.


      • #4
        I had this explained to me just yesterday by a very knowledgeable chassis rep.

        You can get either series of trans with the ISL. Your application should determine what series is best. In a heavy truck with high call volume the 4000 would be a better choice such as for a pumper or quint. A rescue could use a 3000. The 4000 also has more torque converter options then the 3000 which helps the small block ISL.


        • #5
          According to my sources at Cummins the tranny series is based on input TORQUE not HP.Regardless of application.We have a ISM 380 in our Engine.Traditionally,once they are out of warranty,we have them reprogrammed.As this rig has an EVS3000 Cummins advised us that it would be a VERY BAD idea to reprogram this unit as the next jump up would raise the torque curve to the point it would have detrimental effects on the tranny.Personally on anything higher than a 375 I'd be looking to mate it to a 4000.But the input torque is the key to which way you should go,The ISL has a different torque curve than the ISM or the ISX so you'll have to look that up.Best bet is to talk to a KNOWLEDGABLE Cummins or Allison rep who have charts/programs of the do/don'ts and best matches. T.C.


          • #6
            IMHO Cummins 300 - 350 hp and the Allison 3000 series is a good combination.

            In the 400 - 425 hp range i would look seriously at the 4,000 series for high run volume or large hills


            • #7

              ISL with 400 hp and 3000 EVS has been a very normal spec for years....from everyone.


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