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4L60E why the low pressure hot?

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Old 03-30-2015, 06:31 PM
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Default 4L60E why the low pressure hot?

Transmission 4l 60e oil pressure test. When cold it's ok but when it's hot, pressures drops too much.

electrical pin is out Pressure control valve, so full of fishing.

Just came from workshop, all Sonnax $$$$ : Bang:

Last edited by mrvedit; 04-02-2015 at 10:35 AM. Reason: Fix title
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Old 03-30-2015, 10:47 PM
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Your cold pressure is too high. I've been told that max pressure should be between 225 and 240, no higher or seals can blow out.
With a .500/.490 boost valve installed I usually see 225 when I blip the throttle.

So you seem to be too high when cold. Your hot pressures are a bit low for a stock trans and a moderately low if a bigger boost valve was installed.

For ATF, are you running Dex 3 or 6, or something else?
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Old 04-01-2015, 04:43 AM
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Originally Posted by mrvedit
Your cold pressure is too high. I've been told that max pressure should be between 225 and 240, no higher or seals can blow out.
With a .500/.490 boost valve installed I usually see 225 when I blip the throttle.

So you seem to be too high when cold. Your hot pressures are a bit low for a stock trans and a moderately low if a bigger boost valve was installed.

For ATF, are you running Dex 3 or 6, or something else?
Thank you , you are the master . Yes Dex 3 oil.
I did the pressure test with air ... like this.

I wonder if wrong?
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Old 04-01-2015, 05:14 PM
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Your air test isn’t doing anything except blowing oil out of the passages. You need to hook a scanner up to the car and check for trouble codes. Also check the EPC solenoid for proper function hot and cold.
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Old 04-01-2015, 05:59 PM
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Yeah, no idea what that air test would accomplish.

When you say "cold", how cold do you mean? Since you are in Finland, perhaps your idea of cold is very cold. If the high pressure is only when it is very cold out , e.g. -15C or below, I would simply let the car warm up a bit so that trans pressure is never more than 250.
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Old 04-02-2015, 10:24 AM
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I scanned the fault codes and no one was found. I ordered a new EPC solenoid, because I doubt that too. I'll replace all the solenoids with new ones because they are sensitive components.

"Cold " is about 15 celsius ( 60f ) in my garage.
Finnish summer temperature is about ~ 15-30 celsius ( 60f - 86F )
when I use this car .

Yes, car is always needed to warm up before it can be ready for cruising.

The air test tells that when the pressure line " drops down " between the pump and the shell, maybe the oil escapes from there ... warm flexibly?

I am afraid that something from pump has been forgotten, or some part is missed from inside the pump. The lack of a nylon filter could be causing this and mess the pressure too. This problem started in after gearbox maintenance, where
was added for example Sonnax Smart -Tech input input kit.

Would be a huge job to take down the gearbox. So that's why I've been thinking, should I do it.
Attached Thumbnails 4L60E why the low pressure hot?-20150402_181142.jpg  
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Old 04-02-2015, 10:34 AM
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I have been told by a pro trans builder that if that yellow filter is left out of the pump (by mistake) that pressure will be extremely low.

In your (unusual) air test it was interesting to see the fluid escape by the boost valve. That is why I suggest the Sonnax boost valve over the Transgo one - the Sonnax has two o-rings which eliminate this leakage and therefore might have better and higher pressure regulation.

Installing a new EPS sounds like a good idea.

So, the trans was recently rebuilt? Exactly what aftermarket/performance parts were installed?
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Old 04-02-2015, 11:15 AM
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Originally Posted by mrvedit
I have been told by a pro trans builder that if that yellow filter is left out of the pump (by mistake) that pressure will be extremely low.

In your (unusual) air test it was interesting to see the fluid escape by the boost valve. That is why I suggest the Sonnax boost valve over the Transgo one - the Sonnax has two o-rings which eliminate this leakage and therefore might have better and higher pressure regulation.

Installing a new EPS sounds like a good idea.

So, the trans was recently rebuilt? Exactly what aftermarket/performance parts were installed?
Yes, I have Sonnax two O- rings valve .
trans was recently renovated , performance parts installed .

I use the air often many tests , it is much easier .
Attached Thumbnails 4L60E why the low pressure hot?-rain.jpg  
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Old 04-05-2015, 06:24 AM
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The transmission has been taken out of the car.
Yes, the filter was missed from the pump, now in the air test there was no leaks. Great work for a such little thing.

Now look like this, that you should measure the line pressures sometimes, and then you'll ease your life. They are important for the transmission duration.
Attached Thumbnails 4L60E why the low pressure hot?-20150403_185218.jpg  
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Old 06-18-2015, 04:14 PM
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Now the pressure is good. Here, the video on Circle D 3200 RPM .
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Old 06-24-2015, 04:47 PM
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Morjesta vaan Reka.

I had some shifting problems too and i took my own rebuilt tranny apart because of slipping 2 to 3 gear. Didnt found anything special but only leaking reverse/boost valve.
Do you really have o-ring Reverse/boost valve?
Because i had very similar leak like in your video and i changed to o-ring model and air leak was totally gone.
My tranny is just about to go back in car so no real time results yet with my new reverse/boost valve.
Where do you live?
If my problem continues i could use a little help with your HP tuners if you will.
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Old 06-24-2015, 05:04 PM
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I looked your picture with arrows and now i understand it was leak between transcase and pumpcase because of missing filter. Not from reverse/boost valve like mine.
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Old 06-30-2015, 01:41 PM
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Originally Posted by fsvaasam
I looked your picture with arrows and now i understand it was leak between transcase and pumpcase because of missing filter. Not from reverse/boost valve like mine.

Hey , good to find out that you got a leak, it's probably okay.
Yes , in my car it leaked between trans- case and pump case .

Low pressure mess with th whole box functions .

I hope these videos will help to someone ?

And I live in central Finland (Europe)
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Old 06-30-2015, 02:04 PM
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I live in south, so not much help with your HP to me then. I propably by my own HP soon and have wideband lambda to lean out my fuel tune.
I have TSP tune and its very rich. It hardly stays on idle. Lambdas were also quite black when i disassebled them. I have heard with other people too here in Finland that US tune is too rich to our fuel here.
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Old 06-30-2015, 02:59 PM
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Originally Posted by fsvaasam
I live in south, so not much help with your HP to me then. I propably by my own HP soon and have wideband lambda to lean out my fuel tune.
I have TSP tune and its very rich. It hardly stays on idle. Lambdas were also quite black when i disassebled them. I have heard with other people too here in Finland that US tune is too rich to our fuel here.
here Finnish. http://finnshark.com/forum/showthread.php?t=11565:/PB Hurraa:

Last edited by Reka; 06-30-2015 at 03:12 PM.
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