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Thread: 4L80E trans stalling engine

  1. #1
    Join Date
    Feb 2018

    4L80E trans stalling engine

    I have scoured the archived forum posts to get an education on my problem. Iíve found some help but not enough.

    Here are the particulars.

    The trans is out of a 1997 Chevy W3500 which is a tilt cab chassis. The engine is a 5.7 Vortec.

    At 167K I pulled the original trans mainly due to a bad housing crack and bought a Jasper re-maned trans.

    At 197K I pulled the Jasper re-maned trans since it was acting up. Jasper sent me a warranty trans that is now acting up too.

    Clearly I have not had very good luck with Jasper.

    The first trans from Jasper right after install would hesitate to move the truck from a stop.
    At a stop when I wanted the truck to move I could hear an RPM increase but the truck wouldnít move for a few seconds. Then something would catch and it would move. Almost like slipping the clutch on a manual trans for a few seconds.

    Jasperís only solution was to send me a warranty trans to swap out. I elected to continue to drive the trans and swap it out towards the end of the warranty period.

    A few days ago I swapped out the first Jasper trans.

    The second Jasper trans will at times but not all of the time stall the engine when shifted into reverse. This happened on the first test drive.

    On the second test drive the trans would stall the engine at times but not every time when shifted into reverse or drive.

    Jasperís install paperwork required a cleaning of the mass airflow sensor which I did. I changed the air and fuel filtersÖ it was time for it anyway.

    Other than this problem the trans seems OK. It will shift nicely through the gears and the problem with hesitation from a start I had on the first Jasper trans is not there on the second Jasper trans. I can drive the truck without an issue other than at times it will stall the engine at a stop but not at every stop.

    I understand a low fluid level or a poor flow through the trans cooler hoses can cause this.

    I checked and rechecked the fluid level using the proper method to check fluid level. I use Amsoil products in everything I own so I used Amsoil's ATF fluid in this trans

    I doubt I have poor flow through the trans cooler hoses since this problem never happened with the first Jasper trans. The swap of the first to the second Jasper trans happened within a few days. Additionally I used Jasper's cooler flush tool on the first Jasper trans swap. They provided it with the first trans at a minimal additional charge. So the cooler and the hoses were cleaned at 167K.

    If I wanted to absolutely verify the cooler and hoses are open how would I do it? Remove the hoses from the trans and use low pressure compressed air attached to one hose to see the flow from the other hose?

    I donít want to pull this trans for a third time and I doubt I can twist Jasperís arm for another warranty trans.

    Before I go poking around not knowing what I am doing inside a trans Iíd like some advice from those with more extensive knowledge than I have.

    I'm not totally ignorant about auto transmissions. I've installed a few shift kits in the past some requiring drilling of the valve body. Should I spend some cash on a trans diagnostic scanner?

    Lastly Iím not condemning the Jasper trans just yet.

    Any helpful comments will be appreciated.

  2. #2
    Join Date
    Aug 2011
    New Port Beach, CA.
    i have the same problem i found that it is do to low fluid levelyou may have the wrong dipstick or tube and not putting in enough fluid. It may also sputter in first and not hold overdrive.
    6.0 MAX Blown

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