Weird Line Pressure

[CFHMetal]

Good Morning all,

Would someone kindly point me in the direction of the cause of my odd line pressure.

There also seems to be a light shudder at low throttle input.

I am hoping its just feeling more road vibration from the new shocks I've installed but I'm just not sure.

I hope the links work.

Thanks for the help.

Driving:



Startup:

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[ZeroSignal]

Idle looks normal. The TCM is demanding 110psi and getting 108-111.

Mine idles around 110, until I press the brake and TCM demands 125psi.

Can't tell from the video, but when you say it's "stuck at 120" does it not increase under load?

Or are you saying it never drops below 120?

The good news is you're actual pressure and demanded pressure are in sync.

What trans tuning do you have? Stock or upgraded valve body?

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[CFHMetal]

Hello, thanks for reply.

The psi is stuck at 120 when coasting and will go up when accelerating.

The weird thing is that it would usually fall back to 110 when I would let off or at a stop sign, lately it has been 120 and holding there.

Applying the brake to put it in gear it holds 125, once in gear it will jump 150 to 170 before settling.

When starting the truck the pressure jumps to 200psi + and then bounces from 98 to 130psi but very quickly.

It just seems like a broad range to me almost like a sensor or something.

The tuning is DRD and its been good for the last 15k miles or so, just in the last 2weeks its been acting strange.

I'm very confused because the Demand and Actual are right on when driving, its the idle that's weird.

It is a stock valve body with 100000 miles.

I changed the fluid and filters at 87K

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[ZeroSignal]

The fluctuations at startup and shifting from P-R-N-D are normal, since fluid is getting moved around through the valve body and TCC.

Honestly, I wouldn't sweat it staying at 120 while cruising as long as it is shifting normally, TCC is locking and unlocking as it's supposed to, and your fluid temps are in the normal range.

You can always try re-loading your tune file, which will reset the adaptives. Take it back through the drive re-learn and see what values you get.

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[CFHMetal]

Alright, I will reload the tune and ride it out. Thank you for your help Zerosignal.

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[ZeroSignal]

No worries.

Always down to help a fellow Pantera fan.

Once you re-flash the ECM and start your drive re-learn, monitor your demanded pressure, actual pressure, throttle position (keep it under 30%), and TCC state.

You should be able to tell from those parameters if anything odd is happening.

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[Dennis Soucey Jr.]

I had similar issues.

Changed fluid and filters with OEM components.

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