hey guys, 1st post here. hoping to learn from this forum as well as provide any info from my experience with gm vehicles. haven't run across this specific issue i'm having on mine. i have an 07 tahoe LT 2WD 5.3 w/225k miles. i stopped driving it because i started using another vehicle for work. no issues at all before parking. i would start up (no drive) once a week. after a few weeks i noticed a bad trans leak at the driveshaft / u-joint area. leaks when vehicle is not running and has leaked quite a bit. not sure exactly what parts i need to repair correctly. any help would be greatly appreciated

 

its leaking out the center of the slip yoke. you need a new slip yoke

 

thanks! so i'll get a new slip yoke.

should i even bother to replace the shaft sleeve o-ring? can't remember if the housing has to come off for it

 

the transmission output seal can be done at the same time. if it has a circular pin hole...orientate the hole at 6 o'clock. the trans extension housing does not have to be removed.

 

the ujoint is held in with plastic...it has to be melted out...use a torch and it will run out the 2 holes that can be seen in the picture. the new slip yoke will be secured with clips...make sure they come with the slip yolk.

 

2003 Trailblazer 90K miles. Truck was solid until I was hit from behind and I think this may be an unseen result from that time. Any input is appreciated. I'm wondering if yoke or something with that seal (or both) I'll replace both but don't want to get into that seal if its going to be a major situation and can avoid.

 

There is a seal inside the transmission tail housing. If you pull the driveshaft, remove the tail housing, you will see a metal sleeve the goes over the splines where the yoke slips. Inside the metal sleeve there is an o-ring. You can see the o-ring groove on the metal sleeve. That o-ring is what keeps transmission fluid from leaking through the inside of the yoke and out the little hole by the u-joint.