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Thread: 5HP18 Valve Body rebuild question

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  1. #16
    Join Date
    Feb 2015
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    116

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    @Regal:
    I think your 2-3 shift problem had more to do with slammed teeth on the F drum and a bad F drum glide bearing. Because:
    - From 2-3 the G clutch disengages
    - From 2-3 the F clutch engages
    The friction plates IN the G drum that lock into the F drum will, over time, slam the teeth on the F drum meaning it will take a little longer before F engages / disengages
    The bad F drum glide bearing inside the F drum will cause the F piston to move in and out at a slower rate

    This is a typical early 5HP18 fault. You will not nessecarily notice slippage or jerks as the engine indeed stops revving during shift moments. However, when the engine does rev, it will put torque on the G friction plates who will put that torque on the damaged F drum. The result is some slippage since those plates do not instantly grab-hold or release. I have opened up multiple "18" boxes and all show slammed teeth on drum F from plates belonging to drum G.

    Edit:
    I do not exactly know what that correction kit does but I guess it modifies the fluid pressure to G and F. Have never had to use that kit though.

    @whiskeychaser:
    No kind of rev changes, no kind of slippage. It is an instant 2-1 downshift but with a bump. I will check all the shift valves. Thanks for the tip. Solenoids are 100%. Ohm resistance checks out and no gunk in the solenoids or the small pit behind them.


    I have now:
    - Overhauled the valve body I pulled from my car last week (the one originally mounted in 1993)
    - Swapped the 2-1 jerk body with this valve body
    - Refilled tranny.
    Result: no jerk, good shifting.

    I also replaced many springs in the valve body that I mounted last week (the one with the 2-1 jerk). Shift valves, 12345 springs and all kinds of other small springs. Although I have checked every part number and location 100x, I may have done something wrong. I will open up the valve body and see if all has been mounted as it should have been. I DO have to note that replacing those springs gave me:
    - A bit more responsiveness to my throttle management from the transmission
    - Slightly quicker shifts: rrrrRRRRR - rrrrrrrrr instead of rrrrrRRRRRR - - rrrrrrrrrrr
    - All round slightly better feel when upshifting.

    I guess that new springs ensure that all the pistons will almost instantly go back to their position when fluid pressure is lost. Since the springs in the valve body mounted today are original 1993.. they probably lost some of their force meaning the valve body functions a few %'s less effective.

    In any case, I will look over the entire piston / spring layout again. Also important to check is if I have put all the metal clips correctly on the various pistons (although I am sure I have).


    For those of you who would like to know what I have done with the valve body I mounted today, check my YouTube DIY:

    Part 1:


    I added a reference to whiskeychaser and shogun for the info on the pressure regulator.


    To be continued. Thanks for the help.
    Last edited by Frank87; 02-28-2015 at 03:44 PM.

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