Transmission issue 4L60 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Tenncman · 10-15-2018, 05:58 PM

I have never seen this before. I'm wondering if anyone has ran across this issue. I have a transmission leak that is coming out of the transmission front yoke. Not at the seal area , but the center of the yoke.

hugger6933 · 10-15-2018, 07:34 PM

You mean the trans yoke? I had one once that the center had been knocked out. you could take out the driveshaft and look at the yoke it had no center I mean it was gone so I replaced the yoke solved.

Tenncman · 10-15-2018, 07:38 PM

Yes the trans yoke.the center is still there. It's been driving me nuts trying to find the leak. Lol. If I take it out can any trans repair place order me one ?

**AussieinNC** · 10-15-2018, 08:22 PM

The end of the yoke is sealed with a flat metal welch plate...they leak sometimes...

Usually no need to replace the yoke....unless the oil seal area is grooved up beyond repair.

Remove the yoke from the driveshaft by removing the caps in the yoke that center the front universal joint.

Clean the yoke up, then knock the metal flat plate using a small shaft driven from the spline end of the yoke...keep the flat plate to reinstall...

Clean the internal area where the plate seats and clean the plate itself...I use brake clean...look close at the flat plate, it will have a dimpled area on the outer side from where it was installed originally,,,,use a ball head hammer to knock the dimple back out. This will shrink the plate overall.

Mix up some 2 part epoxy and coat the sealing area of the yoke where the plate sits, then reinstall the plate with the convex side out, then expand the plate into the seal area by hitting the center of the plate with 1/2" drift. This will seat the plate back n place and the epoxy will seal it all up.

Spread some more epoxy around the outside of the sealing area....

Let the epoxy dry totally...

Then reassemble the driveshaft universal joint...

While the shaft is out, replace the seal in the extension housing...

Bigdav160 · 10-15-2018, 08:19 PM

Truck yokes have a vent hole in the rear plug.

Truck transmissions use a yoke sleeve to keep them from leaking through the splines and out the hole in the yoke.

Install a sleeve on the output shaft or plug the hole with silicone sealer

Tenncman · 10-15-2018, 10:27 PM

Thanks for all the information on what's been happening and how to fix it on my truck. Glad to run across this great site and helpful folks.

10-15-2018, 05:58 PM	#1
Tenncman Registered User Join Date: Oct 2018 Location: Winchester Tennessee Posts: 21	Transmission issue 4L60 I have never seen this before. I'm wondering if anyone has ran across this issue. I have a transmission leak that is coming out of the transmission front yoke. Not at the seal area , but the center of the yoke.

10-15-2018, 07:34 PM	#2
hugger6933 Registered User Join Date: Oct 2008 Location: Marianna Arkansas Posts: 7,279	Re: Transmission issue 4L60 You mean the trans yoke? I had one once that the center had been knocked out. you could take out the driveshaft and look at the yoke it had no center I mean it was gone so I replaced the yoke solved.

10-15-2018, 07:38 PM	#3
Tenncman Registered User Join Date: Oct 2018 Location: Winchester Tennessee Posts: 21	Re: Transmission issue 4L60 Yes the trans yoke.the center is still there. It's been driving me nuts trying to find the leak. Lol. If I take it out can any trans repair place order me one ?

10-15-2018, 08:22 PM	#4
AussieinNC Moderator Join Date: Jun 2017 Location: Cherryville, NC Posts: 2,204	Re: Transmission issue 4L60 The end of the yoke is sealed with a flat metal welch plate...they leak sometimes... Usually no need to replace the yoke....unless the oil seal area is grooved up beyond repair. Remove the yoke from the driveshaft by removing the caps in the yoke that center the front universal joint. Clean the yoke up, then knock the metal flat plate using a small shaft driven from the spline end of the yoke...keep the flat plate to reinstall... Clean the internal area where the plate seats and clean the plate itself...I use brake clean...look close at the flat plate, it will have a dimpled area on the outer side from where it was installed originally,,,,use a ball head hammer to knock the dimple back out. This will shrink the plate overall. Mix up some 2 part epoxy and coat the sealing area of the yoke where the plate sits, then reinstall the plate with the convex side out, then expand the plate into the seal area by hitting the center of the plate with 1/2" drift. This will seat the plate back n place and the epoxy will seal it all up. Spread some more epoxy around the outside of the sealing area.... Let the epoxy dry totally... Then reassemble the driveshaft universal joint... While the shaft is out, replace the seal in the extension housing... __________________ Family and country before all others... 2006 Chevy Silverado (Daily Driver) 2012 Chevy Equinox

10-15-2018, 08:19 PM	#5
Bigdav160 Registered User Join Date: Apr 2011 Location: Klein Texas Posts: 3,852	Re: Transmission issue 4L60 Truck yokes have a vent hole in the rear plug. Truck transmissions use a yoke sleeve to keep them from leaking through the splines and out the hole in the yoke. Install a sleeve on the output shaft or plug the hole with silicone sealer __________________ My Classics: '72 K20 Suburban + '65 Dodge Town Wagon '72 Corvette Roadster +'67 Corvette Roadster '73 Z-28 Camaro '63 Ford SWB Uni Pickup '50 Ford Coupe

10-15-2018, 10:27 PM	#6
Tenncman Registered User Join Date: Oct 2018 Location: Winchester Tennessee Posts: 21	Re: Transmission issue 4L60 Thanks for all the information on what's been happening and how to fix it on my truck. Glad to run across this great site and helpful folks.



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