Mystery Gearbox Bung?...

[rockandrollcamera]

Hey guys, first post. Hopefully you can help me? Basically went out yesterday to check the oil on me Polo. When I lifted the bonnet the underside of it and all of the engine and bay where kind of sprayed with a greyish sort of liquid. So I had a look around and I found a rubber bung type thing on top of the transmission (veiwable from above when looking down at the engine) that appears to have popped off (still attached by a rubber arm). Referred to the Haynes manual but there is no mention of this bung (though it does show in a few photos). To the best of my assumptions this bung is used for topping up the gear box oil, though the manual says this is done by unscrewing the transmission oil filler/level check hex bolt (their words, not mine). Mine is a 96 Polo and so this bolt is on the front of the gearbox (accessible from the front of the car, under the bumper). So with no mention as to this bung I can only guess that you would unscrew the gearbox oil filler/check bolt as normal, and fill with oil from this bung until it trickles out of the bolt hole at the bottom? Would this be true? I just need to know if this is the case, and what could cause this bung to pop open.

I have noticed that the gearbox has been a bit "clunky" lately, and there has been a slight smell at times entering the car. I ran the engine with the bonnet open and this smell became apparent as soon as I put the car in gear, and also some vapour seemed to appear when a few revs were given, though from the driver's seat I can't say for sure it came from this bung thing.

Any ideas or help, please let me know. Don't really want to drive her of top her up or anything until I know for sure what the problem is and how serious it may be? Cheers guys, will try to add some pictures below if I can...




The transmission oil filler/level check bolt...



The bung hole thingy...



And a closer look...

[alexperkins]

That bung is to check the timing

DO NOT POUR OIL IN THERE lol

Filling the box is done from the higher drain plug, and drained from the lower one.

[rockandrollcamera]

Thanks for that Alex... think that its a bit strange that there is no mention of this in the Haynes manual? I think alot of people would draw the same conclusion that I did, but perhaps not go to the length of checking and make a very messy and expensive mistake!? I couldn't find any info on this anywhere!...

Is there any reason why this plug would have popped open and do you think that it is responsible for the greyish spray over my engine bay?

Also, please explain what you mean by the higher plug and lower plug? To my knowledge all I can find is that there is the one bolt (that I circled) which is unscrewed. If oil flows out your fine, if not then you fill it until oil does flow. Is this incorrect? The other bolts to me seemed to be some kind of retaining bolts, perhaps part of the gearbox or holding on a panel? Of course I could, and probably am, completely wrong? Maybe what I have read is just for checking the level, and what you refer to is emptying and refilling the oil?

Either way, your knowledge is much appreciated and any further light you, or indeed anyone else, could spread is greatly appreciated!

Thanks guys!...

[alexperkins]

They pop open sometimes I wouldnt be too worried

The dust will be clutch dust

The filler is the one you have circled

The drain is under the passenger side drive shaft - have a look and youll see it.

Thats correct, fill it till it overflows.

[sixen]

The bung at the top is for timing, there are marks on the flywheel visable through the bung to ensure TDC when timing up the engine etc. had a few people fill their box up with oil through there, FAIL haha.

a common oil leak place on polo gearboxes, resulting in a wet under carriage etc is from the selector shaft oil seal at the rear bottom. easy cheap fix

[sgard]

just read this thread, anymore info on the selector shaft oil seal, as i have oil leaking in this area.