4L80e trans leaking from "electrical connector"

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Wontonfun

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95 C3500 chassis cab w/ 7.4L and 4L80e having trouble solving transmission leak. Dealership says it's coming from an electrical connector that ties into my wiring harness between my TISS and TOSS. They said it would probably be an oring but they would have to pull the entire transmission to replace. That sound like anything close to being legit?
 

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89obsSB

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You don’t have to pull the trans. That’s there excuse to make more money. I worked in a trans shop for 9 years. Should be able to drop pan and pull valve body down and pull the clip that holds the connector and pop it through to the inside. Replace the oring or the connector/ harness. Depends on where it’s leaking from. Either around the connector (oring) or through the pins.
 

stutaeng

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They are prone to leaking at the connector when they get a bit older and can cause weird shifting. Just drop the pan and change it. No need drop/remove the valve body.

They are around $50-$60.
 

89obsSB

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They are prone to leaking at the connector when they get a bit older and can cause weird shifting. Just drop the pan and change it. No need drop/remove the valve body.

They are around $50-$60.
I couldn’t exactly remember if the valve body had to come down or not. I know on the 6l90 valve body has to come down. But that connector is at the back of the trans. Don’t see much of the 4l80 units at the GM dealer I am at now.
 

stutaeng

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I couldn’t exactly remember if the valve body had to come down or not. I know on the 6l90 valve body has to come down. But that connector is at the back of the trans. Don’t see much of the 4l80 units at the GM dealer I am at now.
Yeah, you are right on the 6L90...Those have like a little locking type connector, right? On the 4L80 I think it's just like 2 bolts from the valve body hold the harness, or may there are just clips there and they can be sprung back to get the old harness out and new one it?


He kinda shows how to do it around the 6:08 minute. Seems pretty easy. Hardest part is probably draining the fluid and dropping the pan:
xc_hide_links_from_guests_guests_error_hide_media

Change the fluid filter while you are it....
 

89obsSB

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Yeah, you are right on the 6L90...Those have like a little locking type connector, right? On the 4L80 I think it's just like 2 bolts from the valve body hold the harness, or may there are just clips there and they can be sprung back to get the old harness out and new one it?


He kinda shows how to do it around the 6:08 minute. Seems pretty easy. Hardest part is probably draining the fluid and dropping the pan:
xc_hide_links_from_guests_guests_error_hide_media

Change the fluid filter while you are it....
Dropping pan isn’t to bad. Some of the units have a drain plug to drain it first.
 
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