What do I unplug to stop the rev limiter in 9th gear?

Discussion in 'Ask An Owner Operator' started by scoobertdoo, Dec 5, 2021.

  1. scoobertdoo

    scoobertdoo Road Train Member

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    Hate my 1500rpm governor in 9th gear. I figure if the truck doesn't know what gear it is in, it will not limit the rpm. Maybe something to unplug so it doesn't know it's in high range? I have an Eaton 10 in a 2016 paccar powered pete

    Don't want to have my truck reprogrammed.
     
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  3. LoneRanger

    LoneRanger Road Train Member

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    Programming is the only way that I can think of. Nothing mechanical would be on a transmission to act as a rev limiter.
     
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  4. Pamela1990

    Pamela1990 Road Train Member

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    Are you sure there isn't just a problem that needs to be fixed.
    Seems odd that they intentionally limit rpm to 1500 in 9th.
     
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  5. scoobertdoo

    scoobertdoo Road Train Member

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    I have an old Corp owned truck. 9th was capped at 1500 and top speed was 65. Got rid of the speed limit, but missed that there was a limit in 9th. Every other gear revs fine, even 10th revs to the moon.
     
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  6. scoobertdoo

    scoobertdoo Road Train Member

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    The truck must know it's in 9th gear?
     
  7. Pamela1990

    Pamela1990 Road Train Member

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    Thanks for the education, never heard of that before.
     
  8. scoobertdoo

    scoobertdoo Road Train Member

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    Makes two of us. I wasn't even aware a manual truck reported the gear to the engine. Welcome to EPA 2017 trucks I guess.
     
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  9. Old Man

    Old Man Road Train Member

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    It doesn’t have to be reprogrammed, just let a dealer reset some parameters, get a print out of how everything is set. You will be surprised at all they can set to control things.
     
  10. scoobertdoo

    scoobertdoo Road Train Member

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    As I understand it, they have to reprogram the ECU, and if they do I have my own program in there that would be erased. My guy quoted me $300 for the job, but really it's not worth $300.
     
  11. AModelCat

    AModelCat Road Train Member

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    If its a manual transmission, there is nothing mechanical on that transmission that registers the selected gear, with the exception of the backup light switch.

    Only thing I can think of is maybe the computer is programmed with tire size and the transmission/rear end ratios and it can calculate the gear based on engine RPM and speed? I don't know, never dug into the parameters on a Paccar.
     
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