stealing oil from the gearbox

[jgah]

Volvo MD 11C , gearbox and Walter V drive.
The oil level in the V drive rises and drops in the gearbox.
Leaking seal is perhaps too simple, I noticed some air escaping from the gearbox when checking the level just after running the engine. Is there a hidden air valve in the gear box wich is closed now?
When the pressure doesn't rise , I assume the "leaking seal" between the gearbox and the V drive is no longer doing so.
Any suggestions would be very welcome.

 

[scottie]

is the V drive water cooled

 

[jgah]

yes.
I think I know what you're thinking, but there is no water leaking. The unit is perfectly dry until the V drive is pushing the oil through it's air valve. At that point there is a significant lower oil level in the gear box. So far, with every check I put back what is too much from "Walter to Tranny"

 

[Graham66]

I had this problem with a Volvo MD turned out to be caused by oil seal problems in the gearbox the shaft works like an "archimedes screw"and moves the oil between gearbox and engine .
As the main engine oil seal is designed to keep oil in the engine the gearbox oil can enter from the gearbox side under the pressure present in the gearbox.

 

[jgah]

thanks for your comment.
Remainig question: does the gearbox have an airvalve?

 

[scottie]

Volvo MD 11C , gearbox and Walter V drive.
Is there a shaft between the g/box and the V drive or is the g/box +Vdrive a combined unit

 

[jgah]

it's bolted together, no shaft visible.
thanks for your comments