Topic: NP 231 front output shaft seal

[AGUHR]

The front seal on my NP231 was leaking slightly so I thought I would change the seal and all would be ok.  Easy enough right?
Changed the seal last night - its seated all the way in and flush. Came out this morning to see a bead of ATF about ready to fall from the flange on the output shaft. Darn it its still leaking. what could I have done wrong?  I didnt think the shaft had any wear marks on it.  I do have a spare NP231 I can cannibalize the front shaft from (but is this bad for the spines?) just to see if it did have wear marks and that is where it is leaking from?

Any ideas?

[AGUHR]

I think I found my own answer - there is a small spline washer intended to seal the splines under the nut. This should be replaced at the same time as the seal itself - but no one knows this and auto stores are useless for this kind of stuff.  I read that gray RTV around the splines (once cleaned really good) and under the nut will solve the leak.  So round 2 tonight when I get home.

[neale_rs]

This same thing happened with my SYE.  The seal rides on the yoke so oil is actually free to come out through the splines unless they are sealed with RTV.  I guess there isn't enough space to place the seal so that it rides on the shaft, which would be the normal way to do it.

[AGUHR]

i was beating myself up this morning when I saw it, so I was running through everything i did. It seemed so simple I thought. Oh well. its a easy fix and cheap so I'm happy.

[sharpxmen]

there's a rubber washer that goes there, i used RTV on my D300 on the splines and behind the nut, not sure how long will last but it doesn't leak so far. if that bead of oil was on the case and not on the yoke then it's not that, i had this problem also and i put RTV on the outside of the seal as well as the inside of the case where the seal sits and let it dry.

[AGUHR]

I'm going to try the rtv on the splines and under the nut before I pull the seal off and have to put a new one in - the last one took me 20 min to pull the darn thing off. They are snug.

[sharpxmen]

I'm going to try the rtv on the splines and under the nut before I pull the seal off and have to put a new one in - the last one took me 20 min to pull the darn thing off. They are snug.

if the oil was on the yoke coming from the splines/nut (that drop you mentioned) it might work.

[AGUHR]

It was - so I'm crossing my fingers.

[AGUHR]

thats what it was. put rtv on the splines let it dry put the yoke back on and rtv after under the nut and all is fine now.

thanks again for all the help -

[Bounty Hunter]

I always use RTV on the splines before sliding a yoke on an output shaft, and no need to wait for it to dry.

When installing a yoke, put a dab of grease on the leading edge so it slides into the seal easily without damage to the new seal.