Another D18 question?

Started to take my transfer case out to re seal it and noticed that gear oil was leaking out of the speedo cable end by the speedo drive.
So my question is, what is the best way to seal the speedo drive so it will not leak out the speedo cable end. Is there a gasket that needs to go between the speedo cable and speedo drive,or seal it with silicone when I put the cable on.

So after stopping all my oil leaks, I developed a new problem with my T/case. It will jump out of high range going downhill in 3rd gear when you let off the throttle. But as long as you keep power to it, it won't pop out. Also it won't happen in 4th gear. I have about .002" to .003" end play on the output shaft.
When I pulled the old T/case i swapped from a 18 case to 20 case and used all the internals that were in good shape out of my old T/case, and did not have this problem before. The only thing I did not do was torque the rear output nut with a torque wrench. Just put it on with an impact wrench. Would this make that much of a difference?

 

I made a rubber seal from an old inner tube. Kinda like what you see in your water hose.

 

Maybe an O-ring of the proper size?

 

Mine also leaked. I found an o-ring to fit in there and that worked pretty well.
Not sure what was stock.

 

Bump for my new question?

 

My old transfer case used to do this. I rebuilt it many times only to find it still pops out of gear and wined loudly. I thought the noise from the transfer case was normal. Then one day I bought a back up transfer case. This is when I find out that the new one was really quiet. Seems the gears in the old case were really worn.

 

A worn or broken spring for the poppet ball that holds the shift rail in position will let it jump out of gear. Good luck Mike. Went out to Prison Hill last weekend, now I have t-case issues to deal with.