Oil leak betwin engine and Gear box

I already had the Seal between the Gearbox and the Engine replaced by two different mechanics, and I still have oil leak in my garage. would anyone have an idea why this is happening? Is there a particular way to put this seal in place? I would appreciate if anyone can help.
Thanks

 

It's possible that the crank has been worn from a old stiff seal. Not sure if there is much you can do about it without removing the crank and getting it machined.

Drz400y might have a idea on how to fix it.

 

There is a kit you can get that includes a sleave that is bonded to the crankshaft and an oversize seal. I believe they cost around $100. Sorry, I don't have any details but I believe you can buy them from bearing shops.

 

It could be blocked PCV valves not relieving the crankcase pressure, so the oil is forced out the rear main seal under pressure.

 

Speedi sleeve part nuimber is Chicago Rawhide CR99331. This is a very thin sleeve that you install over the back of the crankshaft and then install the standard seal.

It may not be the rear seal leaking, could be one of the oil gallery plugs in the back of the block, leaking cam covers, front input shaft seal, sump gasket.

Or may be blocked pcv's as IB says.

The problem needs further diagmostics by the mechanic doing the job. He may even need to run the engine with the gearbox removed to see where it is leaking.

 

Hi everyone, as I explained before, the gearbox has been removed twice to replace the seal, and after each time I had oil leak.
The engine doesn't have any leaks, the PVC valves they seem to be ok.
Maybe the solution is to put a sleeve as drz400y as suggested.
My thanks to everyone.

 

Speedi Sleeve documentation can be found here

 

Thank you Ian

 

i have a feeling its the rocket covers.... the back of the rocket covers are leaking because of maybe worn seals (you cant really tell its them because they can leak on top of the gearbox..

that was my problem...

 

Lol @ rocket covers

Rocker covers

 

Lol @ rocker covers

CAM COVERS!

 

Nissan call them rocker covers




Yes it's stupid.

 

sorry was in a game of poker when i posted that

 

Is it definitely coming from the rear main seal?
Could it be coming from further up the engine and running onto the bell housing?

 

Thanks people, but my engine doesn't have any leeks, as drz400 has explaned is inside the gear box some where. I will leave to the mecanic that has done the job to find it.
Anyhow thank you all

 

You all have mentioned Rocket Cover and others. All around the engine has been checked when the gear box was out, no leaks.