Help with R154 gearbox leaking issue please!

[rwdwiganer]

I'm getting a little stuck for ideas with the issue I've been having so hoping someone can help. I know my box isn't the usual mkiv Supra box but hoping someone more mechanically minded than myself can tell me if my idea to solve my issue could work or not. It seems that the gearbox is pressurising at high rpms and blows oil up through the shifter hole. My R154 box is from a Mk3 Supra turbo. I have since read that this is a very common issue with this type of box but I can't find a real solution on the internet.

I am thinking to fit an expansion tank (the type with a small k&n style filter on top) to the bulkhead in the engine bay and run a breather from the shifter extension housing and one from the fill plug on the side of the box up to the bottom of the tank- so in theory- when the box pressurises slightly when accelerating the oil can pass up the breather hoses to the expansion tank instead of pressurising the seals. My plan to connect the breathers to the bottom of the tank is so when I stop accelerating hard the oil should drain back from the tank and back into the box. Has anyone ever had or heard of a similar issue? Any help with this would really be appreciated!

[bignum]

Fit some sponge in just underneath the shifter.

[Chris Wilson]

A better breather system should work, Nissan GTR 32/33's do something similar.

[rwdwiganer]

Thanks for your replies. I have thought about trying the sponge method I've read about but just seems a bit of a crude fix! I will go with fitting a large breather system and tank and see how I go first before committing to the sponge!