strange gearbox leak

[adkrover]

I recently changed out my old leaky gearbox for a rebuilt leaky gearbox. There are two leaks that I am pretty certain I have located. The first one is coming from what I suspect is the rear output shaft on the transfer case. I see it dripping down the foward face of the rear backing plate of the parking brake. It is only about a drop or three per day and the retailer who supplied the gearbox is sending me a gasket kit so I can replace the seal without having to send the whole thing back. Any tips on replacing the rear seal?

The second and more peculiar is coming from what I believe is the breather on top of the transmission. On my old box, there was a circular recess about 1.5" in diameter with a very small hole in the center (1/16") that I imagine serves as a breather hole. The rebuilt box came with a cap that is about 1.5" in diameter held down by a spring in the same location as the breather from the old box. Why is it a large cap and not like the other????? The leak is coming from around that cap as there is no gasket. Just the cap touching the casing with only the spring pressure holding it in place. Should it have a gasket? Should I seal it with rtv and drill a small hole in the cap? I've included a photo. The cap I am talking about is about top center on the gearbox and painted black. Any experience with this would be very helpfull.

Thanks,

Scott

[I Leak Oil]

The leak around the brake assy could be the output shaft seal or the surface of the output flange it rides on. This can be fixed with a new seal and/or speedisleave. It could also be leaking from the transfercase bottom cover and blowing onto the brake backing plate. It could also be leaking from the area of the speedometer drive housing. As for the filler cover, if you have the old tranny remove your original, fixed cover and stake it to the new gearbox. You'll never get that removable cover to stop leaking.
Jason T.

[adkrover]

Jason,

Thanks. The leak is definitely running down the backing plate from a weep hole in the housing it's mated to so I'm sure it's a seal in there. With the cover leak, you're totally right that I should just swap covers. Anything I should know before pulling the cover. I do have a factory manual and Hayne's (or is it Chilton).

thanks

[cdsrover]

I have read that the cover plates are machined to fit the gearbox they come on and should not be swapped. My old gearbox had the top filler hole as the one in the photo. It did not leak too bad from there; mainly from the worn selector shafts. I used a cork gasket that worked pretty well. The old style filler makes gear oil changes a lot quicker.

[I Leak Oil]

Jason,

Thanks. The leak is definitely running down the backing plate from a weep hole in the housing it's mated to so I'm sure it's a seal in there. With the cover leak, you're totally right that I should just swap covers. Anything I should know before pulling the cover. I do have a factory manual and Hayne's (or is it Chilton).

thanks

Don't change the entire shift rail cover, just get rid of your removable fill cap and set the fixed cap in it's place, stake it in a couple of spots and you're done.
Jason T.