4l80e WOT line pressure high
04-01-2016, 09:29 PM
#1
4l80e WOT line pressure high i rebuilt a 4L80E 500miles ago, dual fed directs, sonnax .500 boost valve. I had an issue with an old pressure gauge (eventually it wouldnt read above 50psi). Just installed a new gauge and at idle pressure in Drive is @100psi, WOT its 350-400, and cruising its around 180-200.
What would cause the high line pressure ? Transmission shifts fine, not hard at all but id rather fix the pressure issue before driving too much more. Nothing in the tune has been adjusted in terms of pressure - only shift time has been changed.
What would cause the high line pressure ? Transmission shifts fine, not hard at all but id rather fix the pressure issue before driving too much more. Nothing in the tune has been adjusted in terms of pressure - only shift time has been changed.
04-02-2016, 08:49 AM
#2
Moderator
Wow that is really high. You might want to verify that with another gauge. The ATD-5550 is only $35 on Amazon.
If it really is that high, don't go anywhere near WOT. I recall a thread showing pictures of a hydraulic passage in the case cracking due to high pressure. With such a crack, the case is toast and the entire trans had to be rebuilt into another case.
Assuming the pressure really is that high, perhaps one of the 4L80E gurus can suggest what might be wrong.
If it really is that high, don't go anywhere near WOT. I recall a thread showing pictures of a hydraulic passage in the case cracking due to high pressure. With such a crack, the case is toast and the entire trans had to be rebuilt into another case.
Assuming the pressure really is that high, perhaps one of the 4L80E gurus can suggest what might be wrong.
04-02-2016, 09:14 AM
#3
Wow that is really high. You might want to verify that with another gauge. The ATD-5550 is only $35 on Amazon.
If it really is that high, don't go anywhere near WOT. I recall a thread showing pictures of a hydraulic passage in the case cracking due to high pressure. With such a crack, the case is toast and the entire trans had to be rebuilt into another case.
Assuming the pressure really is that high, perhaps one of the 4L80E gurus can suggest what might be wrong.
If it really is that high, don't go anywhere near WOT. I recall a thread showing pictures of a hydraulic passage in the case cracking due to high pressure. With such a crack, the case is toast and the entire trans had to be rebuilt into another case.
Assuming the pressure really is that high, perhaps one of the 4L80E gurus can suggest what might be wrong.
04-04-2016, 03:00 PM
#4
So I got a normal pressure gauge, and my electric one is wrong by a long shot! I unplugged the electronics to verify max pressure and had 180psi in Park, Neutral, and all forward gears. 270psi in Reverse. Does that sound good ?
I haven't driven it yet to see what WOT and idle is yet, I want to make sure these pressures are good first. I have a transgo boost valve in it, will that allow higher pressure then stock ? Reason I am asking is my 1-2 shift feels soft, its not slipping just have a hard time feeling it shift. I forget what I drilled the plate to, will check it this weekend.
I haven't driven it yet to see what WOT and idle is yet, I want to make sure these pressures are good first. I have a transgo boost valve in it, will that allow higher pressure then stock ? Reason I am asking is my 1-2 shift feels soft, its not slipping just have a hard time feeling it shift. I forget what I drilled the plate to, will check it this weekend.