oldchevy

1991-4.3L C1500 2WD, 170,000 mi.

Does anyone know why tranny fluid would be coming out of my front u-joint? The spline seal is fine and is not leaking down at all, and there is no fluid leaking down from higher up on the trans. itself either. It really is coming from the u-joint and leaking....a lot (puddles). It is splattering up on the under body right above the u-joint as well.

Is there a pin hole are some type of seal in the u-joint section going into the spline?

RahX

might go to a trans shop and prod those guys for info but the yolk going into your trans has a pinhole from the factory. as far as i know there shouldnt be much fluid in that tailhousnig and if there is enough to filli t up and leak out of that yolk then something is leaking that shouldnt be.

79403ta

i used to work in a transmission shop...I had the same problem on my Father in law's truck he said he would try anything to get it to quit leaking so we put some of that 2 part epoxy the pinhole and it stopped the leak...the truck still runs great this was 2 1/2 years ago and still no leak....

TEXAS-HOTROD

I have done the epoxy trick too, only to have it deteriorate after a while. It's a pain, but the best way to fix it is remove the u-joint from the yoke and weld the hole shut.
I have heard that the hole releases any pressure between the tail shaft and the inside of the yoke, when the suspension compresses and the drive shaft slides forward. Some yokes have a master spline on the inside and should releave the pressure as well. For the several that I have welded, I haven't seen it cause any problems.

RahX

well there are some that dont have the hole from factory. they say not to plug it and the only thing i could see it doing is maybe getting a pressure buildup in the tailhousing there and having it blow by the seal after a time but i really dont think anything super bad is going to happen.

oldchevy

thanks for all the info guys. Is the general thought that it is not a sign of a trans. failure etc. and is not really an issue?

RahX

it isnt a trans failure but i would suspect a seal leaking. there isnt supposed to be enough atf in there to fill up the tailhousing like that. if youre concerned about it go talk to a trans shop and see what they have to say about it.