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GM_4L80E_Transmission_Electrical_Connector

Has the potential to leak about a pint of ATF onto the ground where you park, and if it's really dirty under there, it may not be obvious where it's all coming from.

After spending about 3 hours internet researching ATF leaks in the 1992 Chev 6.5 Turbo Diesel pickup and finding nothing of interest, I decided to post this page and see if it may be of help to others. I also searched for 4L80E electrical connectors, and other combinations but didn't get close to the topic of ATF leaks. I have a rather large leak in the driveway every time I park it, this is a new purchase, and I am attempting to fix the little problems the previous owner had no time to find, he just bought a new truck, that's the American way to fix stuff now a days. I have a few friends that tell me the 6.5 mechanical injection turbos are tuff as nails once you address a few problems, and some have racked up some impressive miles   

One mystery was what type of screw driver point to use to get the connector off, having old eyes, it's a problem seeing close into areas like this. Then I had the idea to use the macro setting on the digital camera and take a picture as I do with lots of other stuff. The answer is now obvious, and a Torx it is! 

Having the title of Senior Citizen, I've seen my share of things that work well, and things that don't. After finding the right torx, and pulling loose this connector, I found the sealing surfaces on the inside of the plug are less than generous, and the flat gasket that compresses between the connector and the block is made of a material a little on the spongy side. The whole sealing arrangement on this one plug looks to have been designed by Girls. An old guy like me would have used an 'O' ring seal and groove in the connector. I did read (somewhere) that this particular connector was discontinued, and Trans Builders have to order the newer one if they want it all new. If I were a betting man, I'd say the new one, (1994 and forward) has the 'O" ring we'd expect, and that the torx screw will provide adequate compression of the 'O' ring to keep a seal. 

 I'd appreciate knowing if you have found similar leaks in your 1992-1993 Chev Truck.  I made a custom gasket, and I'll be coating the cleaned up connector and trans side flange area with black RTV. I'll let it fully cure before firing the engine, I hope this will cure a rather serious leak.

Next we'll attack the mechanical fuel injection pump, I don't know how many people know that this pump is easy to rebuild, it was used in FORDS, Hummers and Chevys, and because of this, it will probably be around for a long time.  Want to learn more about them, check out the 'dieselpage', see ssdiesel for the common parts you might need, google them.. It's 10/10/2006 at 2125 hours, who will, be the first person to find this page?    

Send George email about what you found in your 4L80E

Thanks to a kind reader, we have the following to share...

FLUID LEAK AT TRANSMISSION PASS-THROUGH CONNECTOR #37-71-29 - (Oct 13, 1993)

SUBJECT: FLUID LEAKS AT TRANSMISSION PASS-THROUGH CONNECTOR (NEW WIRE HARNESS AND SERVICE KIT)

 

MODELS: 1991-93 C/K, R/V AND P TRUCKS G-VAN AND ISUZU (EQUIPPED WITH HYDRA-MATIC 4L80-E/4L80-EHD TRANSMISSION)

 

CONDITION:

 

SOME VEHICLES MAY EXHIBIT A FLUID LEAK OUT THE TRANSMISSION PASS-THROUGH CONNECTOR CAUSING MATERIAL DEGRADATION ON VEHICLE SIDE CONNECTOR AND WIRING WHICH MAY LEAD TO ERRATIC TRANSMISSION OPERATION.

CAUSE:

 

"WICKING" OF FLUID BETWEEN WIRE AND INSULATION THROUGH THE PINS AND INTO THE CONNECTOR INTERFACE AND ULTIMATELY TO THE VEHICLE SIDE WIRING.

CORRECTION: (FIGURE 2)

REPLACE THE WIRE HARNESS ASSEMBLY PER YOUR TRANSMISSION SERVICE MANUAL AND INSTALL THIS SERVICE PACKAGE PER INSTRUCTION SHEETS.

DATE OF PRODUCTION: (FIGURE 1)

STARTING MAY 5, 1993 (JULIAN DATE 125), ALL 1993 HYDRA-MATIC 4L80-E/4L80-EHD MODELS WILL HAVE THE NEW WIRING HARNESS.

SERVICE PROCEDURE: (FIGURE 3)

REFER TO THE APPROPRIATE SERVICE MANUAL SECTION FOR PROPER REPLACEMENT PROCEDURES FOR THE TRANSMISSION WIRING HARNESS.

WHEN INSTALLING A S.R.T.A. UNIT OR REPLACING A WIRING HARNESS ON AN ASSEMBLY BUILT PRIOR TO MAY 5, 1993 (JULIAN DATE 125), IT WILL BE NECESSARY TO INSTALL THE SERVICE JUMPER HARNESS INCLUDED IN THE SERVICE PACKAGE. INSTALLATION INSTRUCTIONS ARE INCLUDED IN THIS BULLETIN AND IN THE SERVICE PACKAGE.

WARRANTY INFORMATION:

 

FOR VEHICLES REPAIRED UNDER WARRANTY, USE:

LABOR OP. DESCRIPTION LABOR TIME

K6554 WIRING HARNESS USE PUBLISHED ASSEMBLY REPLACE LABOR OPERATION TIME

K7000 TRANSMISSION ASSEMBLY USE PUBLISHED REPLACE LABOR OPERATION TIME

ADD: TO SPLICE PASS-THROUGH 0.7 CONNECTOR TO VEHICLE

SERVICE PARTS INFORMATION:

PART NUMBER NAME

24200161 *HARNESS PKG.--AUTOMATIC TRANSMISSION WIRING HARNESS ASM. VEHICLE SIDE HARNESS CONNECTOR ASSEMBLY INSTRUCTION SHEETS MISC. ACCESSORIES

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

INSTRUCTIONS:

 

WIRING HARNESS ASSEMBLY

THE ELECTRICAL WIRING HARNESS IS UPDATED WITH AN EXTRA LENGTH ON ONE OF THE CONDUITS LEADING TO THE PRESSURE CONTROL SOLENOID ON THE CONTROL VALVE ASSEMBLY.

WHENEVER SERVICING A 4L80-E/4L80-EHD TRANSMISSION PRIOR TO 1994 MODEL YEAR AND THE ELECTRICAL WIRING HARNESS IS BEING INSTALLED, THE EXTRA SLACK IN WIRE LENGTH FOR THE PRESSURE CONTROL SOLENOID (PCS) CAN BE TAKEN UP BY TWISTING THE CONDUIT ONE TO TWO TURNS WITH THE CONDUIT THAT LEADS TO THE PULSE WIDTH MODULATED (PWM) SOLENOID, THEN THE PWM AND THE PCS CONDUITS CAN BE CONNECTED. THE TWISTED WIRES WILL TAKE UP THE EXTRA SLACK AND WILL PREVENT ANY LOOSE WIRE FROM BECOMING PINCHED OR CRUSHED WHEN THE OIL PAN IS INSTALLED. george i found this in a gm manual

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Input on 2/18/08

I read your page on the plug leak and was glad to see that I wasn't the only one!
I have a 93 Suburban 2500 4x4 with the 4l80e. It was shifting hard from 1-2 so I changed the fluid and filter. I noticed while I was down there that the plug was mighty dirty so I unplugged it to find that it was soaked inside with atf. I cleaned it out and the tranny stopped hard shifting and stopped going into fault mode. Few days later it was wet again so I cleaned it again. I'm not leaking onto the ground but the plug is wet inside with atf all the time and has caused it to do some strange things. I'll have the harness replaced with the updated model and let you know how I like it!
Thanks for the help!
N. Reynolds
Oregon Coast
 

 

 

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All the best!

George B.