4l60e tailshaft seep

[90gmcsierraL59]

This morning I decided to crawl under the truck snd look at everything after 1200 or so miles since L59 4l60E swap and I saw a seep at the tailshaft. No drops hanging and none on the concrete under the truck. I checked the transmission fluid after I got to work and it is still full. I queried a friend who owns a transmission shop and he said to check the yoke for slop, then look to see if it is vented or not. He said if it vented to buy a new seal and the o-ring that goes over the yoke tube inside the tailshaft housing that requires tailshaft housing removal to change. He also said if it isn't a vented yoke I could likely just change the seal and be OK. I will investigate further tomorrow and report my findings. He also said if there is slop in the yoke to get the bushing as well. Is there anything I need to know when pulling the tailshaft housing and any other parts I need?

 

[NickTransmissions]

This morning I decided to crawl under the truck snd look at everything after 1200 or so miles since L59 4l60E swap and I saw a seep at the tailshaft. No drops hanging and none on the concrete under the truck. I checked the transmission fluid after I got to work and it is still full. I queried a friend who owns a transmission shop and he said to check the yoke for slop, then look to see if it is vented or not. He said if it vented to buy a new seal and the o-ring that goes over the yoke tube inside the tailshaft housing that requires tailshaft housing removal to change. He also said if it isn't a vented yoke I could likely just change the seal and be OK. I will investigate further tomorrow and report my findings. He also said if there is slop in the yoke to get the bushing as well. Is there anything I need to know when pulling the tailshaft housing and any other parts I need?

Remove driveshaft, disconnect VSS and then take loose the six 15mm ext housing to case bolts (you can remove the vss first if you want) to remove the ext housing from the transmission case.

Buy the following:
- seal
- ext housing bushing (look for a teflon coated one)
- ext housing-case O-ring
- output shaft O-ring

After you have removed the current seal, carefully inspect the inner diameter of the sealing surface for an out-of-round condition. If you see one, apply a bunch of RTV black to the outer seal diameter and inner sealing bore diameter to make up the gap (if it's egrigiously out of round, replace with a good used ext housing from the junk yard).

Reinstall and torque the bolts to 30-35 ft lbs in a X pattern (start with the bolts at the 3 and 9 o'clock position).

LMK if you have any ?s.

 

[90gmcsierraL59]

Thank you!!!

 

[NickTransmissions]

You're welcome. Check the slip yoke for a groove cut into it by the seal - replace if you can feel the groove with a finger nail.

 

[Drunkcanuk]

Check your slip yoke for rust as well. Didn't notice mine got a bit crusty after not driving for a while, like a year. And the next day noticed the big pool of fluid under the truck. Replaced the seal and hit the yoke with emery cloth to get all the yuck off, been good since.