Anyone ever seen or messed with a GM 4L30E?

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idahovette

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SO....always a silver lining, Vince???
The great news is, it's not pump failure or anything serious. Because it still ran drove. As I was driving it up on the ramps, it was starting to slip out of first, which I'm confident is because it lost so much fluid.

Internally, I'm confident in my work, as proven by the nice returned driveability, shifting, etc.
Very firm, positive shifts, which I haven't ever felt in that truck since I've known this woman.

But something up front decided it had enough.

Thanks for that, whatever you are.

I'm betting my money on a cracked TC, or the front seal is garbage (the new one I put on the transmission)
Needless to say, my heart sank to my shoes when I saw fluid pouring out of the front of the transmission. Because I was done working on it. It was ready for her to go to work monday.


I guess the blessing amongst this adverse situation is that it did it to me, and not to her on her way back.

Winching up a broke down car on the trailer early Monday AM would've been lousy.
 

CorvairGeek

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Most immediate failures are far better that getting 'the phone call', after the catastrophic damage has occurred to the wife, daughter, son, etc.
 

Vbb199

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Faulty front seal. It blew it out.

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HotRodPC

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I'd want to make 100% certain it was defective seal and not something else wrong that caused that happen. I notice the seal bolts in rather than pressed in like most. That would make assume that there is high pressure behind as normal but still I'd want to be certain. A few transmission can have issue blowing front seals out and it's not the seals fault. You probably know, 700r4 is one of those units that has problem pushing the front seal out. There is a hole in the pump you can open up to relieve that pressure a bit but keep the volume of fluid behind the seal.
 

Vbb199

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I'd want to make 100% certain it was defective seal and not something else wrong that caused that happen. I notice the seal bolts in rather than pressed in like most. That would make assume that there is high pressure behind as normal but still I'd want to be certain. A few transmission can have issue blowing front seals out and it's not the seals fault. You probably know, 700r4 is one of those units that has problem pushing the front seal out. There is a hole in the pump you can open up to relieve that pressure a bit but keep the volume of fluid behind the seal.

If you look at the place where the seal was, maybe 10 or 11 o clock, there's a port there,
It's in close proximity of where the seal blew out, but not in the exact location.

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I wonder if that's the issue... I'm gonna order another one tonight and do some reading about issues with seals on the 4L30E.
 

Turbo4whl

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If you look at the place where the seal was, maybe 10 or 11 o clock, there's a port there,
It's in close proximity of where the seal blew out, but not in the exact location.

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I wonder if that's the issue... I'm gonna order another one tonight and do some reading about issues with seals on the 4L30E.

Maybe a pressure spike? Check the pump pressure relief valve for free movement?
 

Vbb199

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That's what I assumed, a random rise in pressure maybe.

The pump pressure is metered by a solenoid.
The PCS or obviously, pressure control solenoid.

I did not replace the solenoids, but replaced the o rings, and cleaned the filter screens on them. It's bolted down by clamps to the valve body.
 

Vbb199

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If this trans keeps f'n with me, I'm gonna make a really big frag bomb out of it and blow a crater in the ground.
 

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