[zukenutter]

Gearbox internals are a bit of a mystery to me, hoping somebody with gearbox knowledge can school me a bit.

I'm currently waiting for a replacement gearbox to arrive but I'm a bit concerned about what may have been causing the current box to purge it's oil.
Pretty much from first swapping the boxes when I did my WT transfer swap the box leaked oil and it wasn't until pulling it recently that I discovered the cause. A bung (term?) had divorced itself from the top of the box, at selector rod level. Initially I thought that was the only issue, so I added a "T" junction and ran my breather past it and up into the engine bay. I'm now thinking that wasn't such a good idea as oil is pushing up the hose and out emptying the box of ample lubricant.

I had thought that it was only happening at highway speeds but last night it happened again at speeds under 80. I have a feeling that overfilling through the standard breather when my filler plug was seized may have been a part of the initial cause.


This plug/bung had blown out or fallen out early on.
I've seen mention of this happening on BigJimny forum but with no explanation.



So, I guess my questions are;

1. Is would there normally be that much oil in the selector shaft area of the box?

2. Is there normally that much pressure that it would force so much oil out through it?

3. Is it maybe a case of oil blockage in the breather drawing more oil because of hydraulic effect?

4. How much effect would over-filling have on this?

5. Are there oil galleries in a gearbox that may get blocked and cause these symptoms?


Keen for all feedback, cheers in advance.

[droverdave]

How much did you overfill it?

There aren't oil galleries as such in the gearbox, the gears just sit in the oil and spin around and pick it up.

I think overfilling could be the cause of your issue. Its only supposed to be enough oil to come out the filler hole.

[zukenutter]

for the last couple of months it wasn't overfilled but still doing it