Slip yoke leak

[Bextreme04]

And the difference between the shaft with the weep hole and without the weep hole is that the non-weep hole yoke has a spline missing to allow space for air in between the yoke and end of the output shaft to vent internally to the trans. Some transmissions don't have a clear path for that pressure to vent inside the case, and therefore they seal the shaft and vent the yoke instead. This prevents the pressure/vacuum cycling inside the tail housing.

 

[Joshua Keith]

If you JB weld it, you are effectively sealing the space there. Which means that every time the shaft tries to slide out it will create a vacuum and every time the shaft tries to slide in, it will generate pressure inside that cavity. The BEST outcome of that is that it blows the JB weld right out the end and you get your leak coming back. The worst case is that the shaft doesn't want to slide and it pushes in on the output shaft of the trans and in on the pinion of the rear diff. That's going to be extra thrust load and premature wear on U-joints and thrust washers in both the transmission and rear end. Its just as much work(or actually probably less) to just pull the rear driveline, take the 4 bolts off for the rear trans housing, replace the output seal on the rear housing(because you are already there) and pop a new o-ring in the output shaft. It's probably a 1 hour job... tops. Then you will be right back to new, non-leaking, operation for about $20 and 1 hour of your time.

If I remember Correctly 4WD trucks don’t have that seal in between the transfer case and driveshaft. I wasn’t able to replace it.

 

[Bextreme04]

If I remember Correctly 4WD trucks don’t have that seal in between the transfer case and driveshaft. I wasn’t able to replace it.

My 4wd truck doesn't have an O-ring on the slip-joint output, but it also doesn't have a weep hole in the yolk. The vent for the entire T-Case is on the housing for the output shaft though, so venting isn't an issue there.

 

[Joshua Keith]

My 4wd truck doesn't have an O-ring on the slip-joint output, but it also doesn't have a weep hole in the yolk. The vent for the entire T-Case is on the housing for the output shaft though, so venting isn't an issue there.

interesting. My drive shaft yoke must be aftermarket then.

 

[seanjournot]

This is why you can't just plug the hole

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[Ricko1966]

Sounds like the RTV is temporary. I think I am going to try some JB weld and see how long it lasts. If it doesn’t work I will look for a yoke that doesn’t have the vent if I can. I have a press so I can replace the unjointed while I’m there. Just a PITA

Never mind. Dead thread.

 

[seanjournot]

bought a farm truck (77 C20) with a sbc 400 for $800. Engine is in the machine shop and I am rebuilding the transmission in the mean time. Was running on propane when I picked it up but would not shift out of first. Looks like a hack job by a farmer really messed up the transmission. These can not operate with axial load, by messing with the yoke they damaged the lower planetary assembly and the input shaft. I think they jammed something plastic down inside the yoke after brazing failed. This caused the yoke to jam creating heavy loads on the output shaft.

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[chevdude]

I'm having the same thing on an 85 Silverado
I did not know that this vent existed.
I'll look and see if that's the cause.

 

[crazyman707]

Oh dear God i hope i didnt permanently damage this ladies truck. It was leaking from that weep hole at the slip yoke and i saw on YouTube people say to RTV it. I told her to wait 1 day to let it dry and she said on the first drive it wasnt shifting out of 1st so she came back home.... it manually shifts to 2nd gear but wont automatically. My confusion is that i dont see a metal sleeve in the tailhousing for that seal yall are talking about. Is there a possibility that the rebuilders forgot to replace it?