2wd th350 output yoke center leak

[fast68chevy]

ok what is the fix for the leaking center hole in 2wd th350 output yoke.. i need to at least stop a couple of the many leaks from the old original th350 in the 75 until i can manage to find a 465 trans and clutch link parts etc to do the swap.... finally,,, some day.... im gonna fix the leaking speedo cable gear bullet o ring seal now and then hope i can do something about the yoke center hole leak next... the front seal i cant do anything about because im not pulling the trans until i put a 4 speed in

 

[CRM]

Typically it's the output shaft seal. Lots of videos on YT.

 

[Matt69olds]

There is a o-ring that seals the yoke to the output shaft inside the extension housing. It’s inside a metal sleeve on the output shaft. It’s purpose is to prevent fluid from leaking around the output shaft/yoke splines.

 

[fast68chevy]

hmm ok where is it at pics? do you have to unbolt the tailshaft ext housing from the trans case to replace this o-ring.

 

[fast68chevy]

Typically it's the output shaft seal. Lots of videos on YT.

its not the seal on the very end of the ext tail housing for the outside of slip yoke. thats dry not leaking.. if thats what you mean.

 

[fast68chevy]

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ok so did some research and its only the 9" tail with two piece driveline trucks that had this sleeve and O ring..
the cars and 6" tail trannies(69-72 trucks) didnt have this.

i wonder about the super long 12" tail TH350 in the big 70s station wagons though...

well i just pulled my shaft housing off the tranny under the truck and finally just got the stupid O ring out of this sleeve so i can replace it now hmm..

it was all hardened and cracked up split...


700r4 used the same ring and seal as TH350.

ACDELCO part # 8654063
o ring seal sleeve


o ring
GM AC Delco 3764601
and my tailshaft bushing is worn pretty good, excessive slop in the bushing the shaft walks aroud more than id like to see.. another reason to ditch this tranny for a 465 tranny which i was already plnning to anyways. if i ever can find the fricking clutch link parts pieces and tranny to do it... impossible here...

 

[taterdog]

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ok so did some research and its only the 9" tail with two piece driveline trucks that had this sleeve and O ring..
the cars and 6" tail trannies(69-72 trucks) didnt have this.

i wonder about the super long 12" tail TH350 in the big 70s station wagons though...

well i just pulled my shaft housing off the tranny under the truck and finally just got the stupid O ring out of this sleeve so i can replace it now hmm..

it was all hardened and cracked up split...


700r4 used the same ring and seal as TH350.

ACDELCO part # 8654063
o ring seal sleeve


o ring
GM AC Delco 3764601
and my tailshaft bushing is worn pretty good, excessive slop in the bushing the shaft walks aroud more than id like to see.. another reason to ditch this tranny for a 465 tranny which i was already plnning to anyways. if i ever can find the fricking clutch link parts pieces and tranny to do it... impossible here...

did this fix the leak ? i'll be taking my housing off to see if i have that sleeve, a hole through my yoke . i thought the sleeves with the o rings were for for the 700r4 only , guess not . mine is a 1984 TH350 so may be different .

 

[Turbo4whl]

@taterdog If your yoke does not have the vent hole (un-venterd), then the plug at the end of the yoke is leaking. Like a freeze plug pushed into the yoke. Look at the yoke splines, are they twisted? If yes, you need a new yoke.

 

[taterdog]

@taterdog If your yoke does not have the vent hole (un-venterd), then the plug at the end of the yoke is leaking. Like a freeze plug pushed into the yoke. Look at the yoke splines, are they twisted? If yes, you need a new yoke.

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This is mine . The yoke has the hole going through it . So no sleeve on the shaft to replace . Do I need to plug the hole in the yoke ? Thanks

 

[Turbo4whl]

Picture of the yoke "U" joint side, and picture of the inside of the yoke please.

 

[xm20k]

The yoke is bored all the way thru to cut the splines it then has a cap and snap ring in the end that can leak. You can see it on this one because its brass most are silver and when covered in junk and assembled on the drive shaft are hard to see.

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I have never replaced the cap or snap ring a new one is like $50-80 depending on length and I just swapped it when I did U joints.

 

[HotRodPC]

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ok so did some research and its only the 9" tail with two piece driveline trucks that had this sleeve and O ring..
the cars and 6" tail trannies(69-72 trucks) didnt have this.

i wonder about the super long 12" tail TH350 in the big 70s station wagons though...

well i just pulled my shaft housing off the tranny under the truck and finally just got the stupid O ring out of this sleeve so i can replace it now hmm..

it was all hardened and cracked up split...


700r4 used the same ring and seal as TH350.

ACDELCO part # 8654063
o ring seal sleeve


o ring
GM AC Delco 3764601
and my tailshaft bushing is worn pretty good, excessive slop in the bushing the shaft walks aroud more than id like to see.. another reason to ditch this tranny for a 465 tranny which i was already plnning to anyways. if i ever can find the fricking clutch link parts pieces and tranny to do it... impossible here...

Good Job here. I believe you get it now. However, I'm hoping you replaced the rear seal too as the guy mentioned in the very 1st post. It may not have been leaking at all, but now that you've disturbed it pulling the extension housing off, and if your O ring was this dried out and cracked up, you can just about be assured your rear seal is just as dry and aged. Now that you disturbed it, it's likely going to leak now. It's only a few bucks, I'd replace it while the extension housing is off if not to late. Even if you have put it back, you can still change it. Maybe even easier to replace with it bolted on the trans case since now it'll stay still while you hammer and pry the old one out, and tap the new one in. It only means removing the driveshaft and then there it is, plenty of access to do while the extension housing is bolted to the trasnmission. I'd love to be wrong, but with that being that old, I'd almost bet at least a chocolate chip cookie that it's going to leak now. I may even raise my bet to 2 Oreos that if it's not leaking now, it's going to very very soon.

 

[taterdog]

Picture of the yoke "U" joint side, and picture of the inside of the yoke please.

 

[taterdog]

The yoke is bored all the way thru to cut the splines it then has a cap and snap ring in the end that can leak. You can see it on this one because its brass most are silver and when covered in junk and assembled on the drive shaft are hard to see.

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I have never replaced the cap or snap ring a new one is like $50-80 depending on length and I just swapped it when I did U joints.

Isn’t it supposed to vent somehow though ?

 

[Turbo4whl]

Isn’t it supposed to vent somehow though ?

Some have a vent hole in the plug. Those need the "O" seal and holder like Randy posted.

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There are several styles of this also, some have a spring. Since your picture does not show an "O" ring holder, the yoke you need should not have a vent hole.

Note: The trans fluid level is lower than the rear yoke splines. When parked the yoke will not leak if the truck is parked nose down. If you park on a hill with the front up, then it will leak.