The Stovebolt Site Forums The Shop Area Engine Shop leak around driveshaft spline?

Rebuilding a '56 3600 & have replaced all the seals (and a lot of the bearings) in the driveline (it's a NAPCO, so $ times 2 for everything).

Finally at the stage to fill things up with oil this weekend and the driveshaft heading into the front axle starts leaking from what appears to be the splines of the pinion gear (not around the seal!?! Oil is coming out from the end of the yolk, not behind the dust cover).

Any ideas what might be causing this, and how to fix it? Is it wore that bad (doesn't appear to be?) that it's leaking through the splines? So far, the rear one is fine/no leaks.

I've thought about siliconing the splines before sliding the yolk on, but that seems like quite a shortcut...

Thanks.

I think there was a posting some time ago about a similar problem with the yoke on the rear end of a 1 Ton.

don't mean to be insulting, but, is the seal in backwards?

not being familiar with your rear axle, but sounds like perhaps something is missing. how did the nut tighten up on the pinion as it has to bottom up against something.. there should be a shoulder or whatever for the yoke tightens up against. usually a bearing and there may be an oil slinger or whatever (missing) between the brg and the yoke. the splines where the yoke goes over the pinion are fairly snug and not sloppy
ron

Don't worry about insults guys. I hang the ego & dignity on a nail as I walk in the garage every nite. Sometimes I pick them up on the way out, sometimes I don't...

Seal looks ok (right way), so after a little scratching we pull the rear end apart tonight (leaker was the front end). Just like padresag says, we left a spacer out of the front axle. This truck was my distraction earlier this year when I got to add "cancer survivor" to my list of accomplishments, so I'm going to assume it was a night when my mind wasn't quite where it was supposed to be (or at least it wasn't in the garage with me).

So this spacer will bind up between the bearing and the seal (and felt pad) to keep this from happening? Guess that's an obvious question, but can't picture that in my head quite yet...

just the machined surfaces and the pressure of the pinion nut keep the surfaces tight and from fluid leakage. none of those parts need any clearance to move against each other. you need a seal where there are moving surfaces
ron