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Thread: 68rfe line pressure fluctuating

  1. #1
    Tuner in Training db.charlie@yahoo.com's Avatar
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    68rfe line pressure fluctuating

    I just installed revmax's billet channel plate and bonded separator plate as well as sonnex's billet accumulator pistons/cover, ssv plug and a Mag-Tec deep trans pan into my 07.5 68rfe.
    Made sure everything was put in correctly according to the instructions. On the channel plate, since i wanted to run higher line pressure, I left the 1/8 inch hole like instructed. i have been playin with hp tuners for the trans for the last two or three weeks. Modifying things here and there, getting the hang of it. i got all my shift points where i wanted them. played with when the TC locks and unlocks. i also played with the pressure a bit. everything was working great before i pulled the pan this morning.

    Before i started the truck, i flashed in another tune with higher max line pressure of 225 psi. at idle/ neutral the desired line pressure is 120 psi. I changed all of the max per gear to 225 psi as well. The problem I'm having now is, at idle, my desired LP is 120, but actual LP is fluctuating from like 50 psi to 200 psi. Is this something in the tune or did I install something incorrectly? are The Billet channel plates designed to be run at 225 psi all the time or can i have lower psi at idle and low throttle?

    I'm planning on calling revmax and randys transmission tomorrow to ask their opinion. just seeing if anyone has run into that on here tonight.

    Thanks

  2. #2
    Advanced Tuner
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    Is the pump spinning fast enough at idle to MAKE 200psi?
    If in doubt, multiply everything by 1.1.

  3. #3
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    Min desired pressure leave as stock
    Last edited by Jim P; 11-12-2021 at 11:12 AM.

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  5. #5
    Tuner in Training db.charlie@yahoo.com's Avatar
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    Thank you for attaching that link Jim P. I read through that several weeks ago but couldn't find it again. I have a screenshot of the max shift pressure per gear table from that thread. I feel I've looked at every 68rfe thread I could find.

    Last night I changed some of the pressures back to stock down low. My problem ended up being that I drained more fluid out than I thought and was two quarts low. When I checked it in neutral, after adding 10 qts back in, it was reading fine. Checked it a little while later and it was low. So I got some more fluid in it and by then the pressures stabilized from 50-200 to 115- 125. This morning the pressures stayed within 5-10 of desired LP

  6. #6
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    I would still keep the min desired pressure at stock

  7. #7
    Potential Tuner
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    I have a 2008 68RFE, and I want to get the HPTuner to start to tune my transmission. Before I make the purchase, does anyone know if the max and min line pressure settings refrenced in the link are available for that year?

    Thank you