LS / 4L80 Transmission leak - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Gordonr1973 · 02-18-2013, 02:31 PM

Hi all;

just trying to figure out a mystery here....I replaced the internal harness last year with another.

Since then I've noticed a small leak that looked like it was coming from inside the connector.

Last night I totally cleaned the connector and trans and this is what I found in the morning.

Is there an o-ring or seal on the inside that might be crushed? I don't want to drop the pan again to work on this if it is a common issue but I don't want it leaking all over for the next 10 years either.

Thanks!

BR3W CITY · 02-18-2013, 05:04 PM

There is an o-ring type seal on the outside of the plug, it fits into a little groove. No clue if there is a part number for it, but I'm sure any ATF resistant o-ring in the right size would work fine.

Wasted Income · 02-22-2013, 11:31 AM

I've been wondering about this too. Does the weaterpak seal this up? I know there's an o-ring that seals the connector to the case, but the leak INSIDE the connector seems like it would be sealed by the plug?

OldCreek · 02-22-2013, 01:10 PM

Some of those connectors develop a leak around the metal pins... which would necessitate a new connector.

ls1nova71 · 02-22-2013, 01:11 PM

Pretty sure you'll have to replace the plug, it's supposed to be a sealed unit that has an o ring on the outside that seals to the case. You have to drop the pan, remove the inside harness and squeeze the retainer tangs on the inside to remove it. Also make sure your transmission vent isn't clogged, when the trans heats up, pressure builds in the case and if the vent is plugged it will force fluid past the weakest seal.

BR3W CITY · 02-23-2013, 05:45 PM

I guess you could pour a tiny bit of chemsafe epoxy in there and re-seal it....but I bet you a quart of it would cost the same as a new plug.

Gordonr1973 · 02-24-2013, 08:00 PM

Thanks guys,

It seems to be leaking from the pins. The vent is clear as well as it looks like it has vented a bit of hot air over last summer.

I haven't done anything with it yet as I'm fixing on the body still. Will do something with it Friday this week.

Wasted Income · 02-25-2013, 09:52 AM

Yeah, after I posted, I did some digging. Seems that the internal harness is a pretty common replacement part, after it starts leaking at the pins.

Got one coming from Rockauto for like $35 shipped.

Gordonr1973 · 02-26-2013, 01:03 AM

Quote:

Originally Posted by Wasted Income

Yeah, after I posted, I did some digging. Seems that the internal harness is a pretty common replacement part, after it starts leaking at the pins.

Got one coming from Rockauto for like $35 shipped.

What was the part number at RockAuto....I'm having trouble finding it on their online catalog.

Wasted Income · 02-26-2013, 01:14 PM

Quote:

Originally Posted by Gordonr1973

What was the part number at RockAuto....I'm having trouble finding it on their online catalog.

http://www.rockauto.com/catalog/moreinfo.php?pk=1489964

AC Delco 24241218

Gordonr1973 · 02-27-2013, 03:24 PM

Thank you!

Gordonr1973 · 03-06-2013, 09:41 PM

There is a spring that fel out while I was working on the tranny....any idea of where the other kind of square end hooks onto?

Wasted Income · 03-07-2013, 10:35 AM

This is about the best pic I have of when mine was apart. Hope it helps, but it probably won't. lol

Gordonr1973 · 03-10-2013, 06:12 PM

Just incase someone searches for this topic in the future, that spring goes underneath on the floppy plate thing that I've highlighted under the plate that bolts on top. There is a cut out portion there that you will see that the square end of the spring goes under.

Clear as mud?? ;-)

02-18-2013, 02:31 PM	#1
Gordonr1973 Home Built '87 Join Date: May 2010 Location: Calgary, Alberta Canada Posts: 1,829	LS / 4L80 Transmission leak Hi all; just trying to figure out a mystery here....I replaced the internal harness last year with another. Since then I've noticed a small leak that looked like it was coming from inside the connector. Last night I totally cleaned the connector and trans and this is what I found in the morning. Is there an o-ring or seal on the inside that might be crushed? I don't want to drop the pan again to work on this if it is a common issue but I don't want it leaking all over for the next 10 years either. Thanks! Attached Images __________________ Gordon 1998 White Chev ext cab 2WD (Summer Project) http://67-72chevytrucks.com/vboard/s...d.php?t=408424 1987 Chev Silverado SWB (Winter Project Rebuild) http://67-72chevytrucks.com/vboard/s...d.php?t=424833 Truck Club http://67-72chevytrucks.com/vboard/s...d.php?t=466969

02-18-2013, 05:04 PM	#2
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: LS / 4L80 Transmission leak There is an o-ring type seal on the outside of the plug, it fits into a little groove. No clue if there is a part number for it, but I'm sure any ATF resistant o-ring in the right size would work fine. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

02-22-2013, 11:31 AM	#3
Wasted Income Boosted Member Join Date: May 2002 Location: Mackinaw, IL Posts: 2,200	Re: LS / 4L80 Transmission leak I've been wondering about this too. Does the weaterpak seal this up? I know there's an o-ring that seals the connector to the case, but the leak INSIDE the connector seems like it would be sealed by the plug? __________________ 1972 2wd K/5 Blazer Turbocharged 370 LSx - 941 rwhp / 1093 rwtq 1969 Chevy K-10 L33 5.3 / 4L80E / NP241 / 4" lift 1964 Buick Skylark Twin TURBO 383 LS pro-touring project 2014 VW Passat TDI - Daily Driver Turbo diesel 2015 Sierra Denali HD Duramax Turbo diesel 2016 Ford Explorer Sport - Twin Turbskis 2017 Polaris RZR Turbo 2014 Nor-Tech Center Console - Twin Supercharged Outboards *TURBO ALL THE THINGS!!*

02-22-2013, 01:10 PM	#4
OldCreek Registered User Join Date: Jan 2007 Location: Central Coast California Posts: 1,026	Re: LS / 4L80 Transmission leak Some of those connectors develop a leak around the metal pins... which would necessitate a new connector. __________________ 1972 K20 Suburban 5.7/700r4/NP205 Dana 44/H052 Sold 1972 C10 5.3L/4L60E 12bolt 5Lug - Sold 1971 K5 Blazer 6.0L LQ9 4L60E NP205 Dana 44/H052!!! 1970 K3500 1ton CrewCab 8.1L/Allison1000/NP205 Dana 60/14B!!!! - Sold 1984 K10 SWB 7.4L/4L80e/NP208 Corp 10/12 bolt Sold 1988 V30 CCLB 7.4L/TH400/NP205/Dana 60/Dana 70/3.73!!! (Sold) 2003 K2500HD 8.1/Allison1000/NP263

02-22-2013, 01:11 PM	#5
ls1nova71 Registered User Join Date: Dec 2009 Location: Independence Mo Posts: 4,118	Re: LS / 4L80 Transmission leak Pretty sure you'll have to replace the plug, it's supposed to be a sealed unit that has an o ring on the outside that seals to the case. You have to drop the pan, remove the inside harness and squeeze the retainer tangs on the inside to remove it. Also make sure your transmission vent isn't clogged, when the trans heats up, pressure builds in the case and if the vent is plugged it will force fluid past the weakest seal. __________________ My '72 short bed build. http://www.ls1tech.com/forums/conver...6-0-4l80e.html 5.3 swap into my RUSTY '71 C10 http://ls1tech.com/forums/conversion...71-c-10-a.html

02-23-2013, 05:45 PM	#6
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: LS / 4L80 Transmission leak I guess you could pour a tiny bit of chemsafe epoxy in there and re-seal it....but I bet you a quart of it would cost the same as a new plug. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

02-24-2013, 08:00 PM	#7
Gordonr1973 Home Built '87 Join Date: May 2010 Location: Calgary, Alberta Canada Posts: 1,829	Re: LS / 4L80 Transmission leak Thanks guys, It seems to be leaking from the pins. The vent is clear as well as it looks like it has vented a bit of hot air over last summer. I haven't done anything with it yet as I'm fixing on the body still. Will do something with it Friday this week. __________________ Gordon 1998 White Chev ext cab 2WD (Summer Project) http://67-72chevytrucks.com/vboard/s...d.php?t=408424 1987 Chev Silverado SWB (Winter Project Rebuild) http://67-72chevytrucks.com/vboard/s...d.php?t=424833 Truck Club http://67-72chevytrucks.com/vboard/s...d.php?t=466969

02-25-2013, 09:52 AM	#8
Wasted Income Boosted Member Join Date: May 2002 Location: Mackinaw, IL Posts: 2,200	Re: LS / 4L80 Transmission leak Yeah, after I posted, I did some digging. Seems that the internal harness is a pretty common replacement part, after it starts leaking at the pins. Got one coming from Rockauto for like $35 shipped. __________________ 1972 2wd K/5 Blazer Turbocharged 370 LSx - 941 rwhp / 1093 rwtq 1969 Chevy K-10 L33 5.3 / 4L80E / NP241 / 4" lift 1964 Buick Skylark Twin TURBO 383 LS pro-touring project 2014 VW Passat TDI - Daily Driver Turbo diesel 2015 Sierra Denali HD Duramax Turbo diesel 2016 Ford Explorer Sport - Twin Turbskis 2017 Polaris RZR Turbo 2014 Nor-Tech Center Console - Twin Supercharged Outboards *TURBO ALL THE THINGS!!*

02-27-2013, 03:24 PM	#11
Gordonr1973 Home Built '87 Join Date: May 2010 Location: Calgary, Alberta Canada Posts: 1,829	Re: LS / 4L80 Transmission leak Thank you! __________________ Gordon 1998 White Chev ext cab 2WD (Summer Project) http://67-72chevytrucks.com/vboard/s...d.php?t=408424 1987 Chev Silverado SWB (Winter Project Rebuild) http://67-72chevytrucks.com/vboard/s...d.php?t=424833 Truck Club http://67-72chevytrucks.com/vboard/s...d.php?t=466969

03-06-2013, 09:41 PM	#12
Gordonr1973 Home Built '87 Join Date: May 2010 Location: Calgary, Alberta Canada Posts: 1,829	Re: LS / 4L80 Transmission leak There is a spring that fel out while I was working on the tranny....any idea of where the other kind of square end hooks onto? Attached Images __________________ Gordon 1998 White Chev ext cab 2WD (Summer Project) http://67-72chevytrucks.com/vboard/s...d.php?t=408424 1987 Chev Silverado SWB (Winter Project Rebuild) http://67-72chevytrucks.com/vboard/s...d.php?t=424833 Truck Club http://67-72chevytrucks.com/vboard/s...d.php?t=466969

03-07-2013, 10:35 AM	#13
Wasted Income Boosted Member Join Date: May 2002 Location: Mackinaw, IL Posts: 2,200	Re: LS / 4L80 Transmission leak This is about the best pic I have of when mine was apart. Hope it helps, but it probably won't. lol __________________ 1972 2wd K/5 Blazer Turbocharged 370 LSx - 941 rwhp / 1093 rwtq 1969 Chevy K-10 L33 5.3 / 4L80E / NP241 / 4" lift 1964 Buick Skylark Twin TURBO 383 LS pro-touring project 2014 VW Passat TDI - Daily Driver Turbo diesel 2015 Sierra Denali HD Duramax Turbo diesel 2016 Ford Explorer Sport - Twin Turbskis 2017 Polaris RZR Turbo 2014 Nor-Tech Center Console - Twin Supercharged Outboards *TURBO ALL THE THINGS!!*

03-10-2013, 06:12 PM	#14
Gordonr1973 Home Built '87 Join Date: May 2010 Location: Calgary, Alberta Canada Posts: 1,829	Re: LS / 4L80 Transmission leak Just incase someone searches for this topic in the future, that spring goes underneath on the floppy plate thing that I've highlighted under the plate that bolts on top. There is a cut out portion there that you will see that the square end of the spring goes under. Clear as mud?? ;-) Attached Images __________________ Gordon 1998 White Chev ext cab 2WD (Summer Project) http://67-72chevytrucks.com/vboard/s...d.php?t=408424 1987 Chev Silverado SWB (Winter Project Rebuild) http://67-72chevytrucks.com/vboard/s...d.php?t=424833 Truck Club http://67-72chevytrucks.com/vboard/s...d.php?t=466969



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