Break down on a 4L75E

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Feb 21, 2018 | 07:49 PM

#21

mOtOrHeAd MiKe

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From: Saskatchewan, Canada - where arguing "DA" is for the slow and weak...

Quote:

Originally Posted by b4ccamaro1le

Pump rotor looks standard to me. Is there something else to check?

Here are some pics on the 3rd acc check valve. I'm thinking its the standard one.

Yup, 13 vanes. As for the servo check valve I would have thought it was standard practice to put it in with the billet servos? If you do add it ensure that you drill out the hole in the body of the valve to match the servo sizes.

Feb 21, 2018 | 08:27 PM

#22

clinebarger

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From: Fort Worth, Texas

Quote:

Originally Posted by 06GR

My plastic piston hard a hairline crack after 80k miles. Why not go aluminum since he has it apart?

Tore down a 2003 4L65E out of a Yukon Denali today with 247,000 miles on it, The piston was it perfect shape other than a little wear at the pin bore. Got replaced with a OE GM part.

Aftermarket aluminum pistons have issues of their own, I have seen many galled-up housings as a result.

Feb 21, 2018 | 09:17 PM

#23

clinebarger

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From: Fort Worth, Texas

Quote:

Originally Posted by b4ccamaro1le

I'm sure the plastic ones would do just fine but I've got the aluminum ones already and it would pain me to leave them out.
I'm sure we won't have a problem with the HE band but when they advertise a wider one you would expect a wider one. It's just irritating.
Here is the space plate as it came. The holes circled are the ones that were different from 5 old stock ones that I have pulled out.

Anybody know what the upper right one is?

The one you have marked .122" is the "orificed" Shift Valve Exhaust for the 2nd Clutch. It is responsible for metering exhaust of the 2nd clutch circuit during 2-1 automatic/detent/L1 shifts.

Feb 21, 2018 | 10:51 PM

#24

1FastBrick

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From: JunkYard

Quote:

Originally Posted by mOtOrHeAd MiKe

The input and output shafts - are they 300M or just hardened/heat treated stockers?

Curious to know what it has for a pump rotor.

The shafts are induction hardened OE shafts. Possibly from Sonax as well.

They are 300mm shaft as opposed to the earlier 298mm stye for the convertor not 300M material.

Not sure if the rotor in these is billet or not.

Hope that helps.

Feb 22, 2018 | 12:20 PM

#25

Choda

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From: Buffalo NY

thank you guys for the detailed write up and pics. So far, it seems like a nice unit.

I agree with questioning the plastic pistons and non-billet pump rotor.

Feb 22, 2018 | 12:48 PM

#26

b4ccamaro1le

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They are saying its got a heat treated stator shaft and induction hardened turbine shaft. Isn't the turbine shaft what we are calling the input shaft?
I don't know how to tell if they are hardened or not.

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Feb 22, 2018 | 12:50 PM

#27

1FastBrick

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From: JunkYard

Those look like the new sonnax shafts which are heat treated.

Feb 23, 2018 | 09:44 AM

#28

b4ccamaro1le

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Here are the 2-3 shift valve and boost valve.
Can someone tell me how to measure or find out what size boost valve this is?
The 2-3 is the Sonnax Heavy Duty 2-3 Shift Valve 77754-41.

Attached Thumbnails

Break down on a 4L75E-img_6812-marked.jpg

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Feb 23, 2018 | 05:57 PM

#29

clinebarger

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From: Fort Worth, Texas

Measure the "Torque Signal" spool diameter (Arrow)

Feb 24, 2018 | 07:38 PM

#30

mOtOrHeAd MiKe

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From: Saskatchewan, Canada - where arguing "DA" is for the slow and weak...

Man, this thing is a pretty good unit right out of the box.

Feb 25, 2018 | 06:01 PM

#31

b4ccamaro1le

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The spool measured at .471". I think that is the stock size right?

Over the next few days I will pull everything out of the valve body. The H3 uses a dif VB than what came on the 4L75. Is there anything else that I should look for as an upgrade?

We got the trans out of the H3 on Saturday and will have the output shaft in hand for the 4L75 pretty quick.

Last edited by b4ccamaro1le; Feb 25, 2018 at 06:06 PM.

Feb 26, 2018 | 09:59 AM

#32

mOtOrHeAd MiKe

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From: Saskatchewan, Canada - where arguing "DA" is for the slow and weak...

Quote:

Originally Posted by b4ccamaro1le

Yeah, that is stock-sized. You may want to move up to a .500" boost valve.

Here is what I put in my 4L70E: https://ls1tech.com/forums/automatic...l#post19783939

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