E4od low line pressure causes
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E4od low line pressure causes
My general question is what could cause low line pressure in all gears on an e4od? Is there anything besides a bad pump that would cause this, such as loose feed bolts or valve body bolts?
Back story...
I was having slow, lazy shifts 1-2 and occasionally 3-4, when hot . Cold the trans shifted great. Progressively has gotten worse. So I figured I should probably bite the bullet and crawl under to check line pressure (was hoping to find it low in just forward and go after the feed bolts). When cold, 150+ psi in all gears, at idle. When hot I get 30-50psi in all gears, including reverse, depending on how long I've run it, but the pressure doesn't change between gears at idle.
I get 200+ psi at stall, and when driving it's around 140 psi. It's also around 130-140 when I get my hung/slow 1-2 shift. If I drop to 2 from D when's it's hund it will shift.
Is there any reason to check this trans further, be it loose feed bolts or otherwise, or am I just wasting time I could be using to pull this trans out. My understanding is that low reverse pressure means rebuild time, but would welcome thoughts.
Thanks,
Ben
Back story...
I was having slow, lazy shifts 1-2 and occasionally 3-4, when hot . Cold the trans shifted great. Progressively has gotten worse. So I figured I should probably bite the bullet and crawl under to check line pressure (was hoping to find it low in just forward and go after the feed bolts). When cold, 150+ psi in all gears, at idle. When hot I get 30-50psi in all gears, including reverse, depending on how long I've run it, but the pressure doesn't change between gears at idle.
I get 200+ psi at stall, and when driving it's around 140 psi. It's also around 130-140 when I get my hung/slow 1-2 shift. If I drop to 2 from D when's it's hund it will shift.
Is there any reason to check this trans further, be it loose feed bolts or otherwise, or am I just wasting time I could be using to pull this trans out. My understanding is that low reverse pressure means rebuild time, but would welcome thoughts.
Thanks,
Ben
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Joined: Jan 2004
Posts: 19,760
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From: St Louis
Either a weak pump or an inadequate restriction downstream of the pump will cause low line pressure readings. The "inadequate restriction" category would include any of the following: Leaky seals or gaskets, loose bolts, valve body problems, etc.
Since you are seeing 200+ psi at stall speed, it probably isn't the pump.
Since you are seeing 200+ psi at stall speed, it probably isn't the pump.
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