speedo cable/gear box

[sco3y]

does anyone know if a gear box builds up pressure while driving.
the problem im having is.
when i drive my car around for a while my left foot gets gear box oil dripping on it. i have traced where it is leaking from after ripping half the dash out and it was the speedo cable connection that goes into the clocks. ok so new speedo cable needed. so off with the old one just to look at it and to see if i can do a quick fix.  i remember having problems with this cable leaking all over my gear box when i first got the golf. it was the 10 mil nut that keeps the cable in the gear box. it was cross threded and worn and the rubber seals were leaking oil  from there. so i had to re tap it with a bigger bolt and ooops. i drilled too far.  so i fitted the new nut and loads of gasket sealer and the leak was fixed . now i have come to remove the cable due to the latest leak and  the new bolt hole i tapped gives a gush of compressed air when i remove the bolt.
so is there a problem with my gear box.
one other thing.
if  the speedo cable is knackered and it has cracks in places around the plastic coating, would this not realese the pressure and leak oil from cracks instead of leaking oil behind the dash.

i forgot to mention the car is a mk 2 golf gti 8 valve on a 89 g plate.
thanks.

[mk1]

There is a breather on the g/box close to where the gear linkage and reverse switch is, check that.
Steve.

[sco3y]

thanks  mk1.  
i will check it in the morning.

[sco3y]

first thing this morning i checked my gearbox for a breather pipe but could not find one.
haynes manual out  and only breather pipe showing was for the older gearbox. so back to the car and look for anything that looks like a pipe or a hole.
i found a little plastic cap on top of a 1" steel tube located at the top of the gearbox just near a sensor (as mk1 said) and it was stiff as f**k to get off.  the plastic cap was stuck on through rust from the pipe. inside the pipe was clean and looked fine. back to the haynes manual to see if this is the breather pipe, i could not find anything in the manual relating to this pipe so f**k it, i toped gerbox up with oil and cleaned everything up and wiped exccess oil from under my dash and i drove the car around for few miles to get it warmed up and waited for the oil drip.
so far so good no oil drips yet after 15 miles of driving.
so i take it it must be a breather pipe i cleaned up then.
cheers mk1. you have saved me the price of a speedo cable/a garage cos i was giving up/ and bottles of oil needed for topping up/ oh and my shoes.
cheers.

[richandhazel]

That plastic cap is your breather. It should clip on securely but once on should feel loose, if you know what I mean. Sounds like yours would have been blocked........hence the pressure build up.