gearbox oil leak - VW 1.9PD Tdi 5 speed

[Toilet Duck]

Afternoon all,

I'd appreciate any help pin pointing a suspect leak on the 5 speed manual gearbox (code JDA) on my 2006 VW Polo 1.9tdi.

I was going to do the cambelt yesterday, but found the engine undertray wet with oil. The underside of the gearbox casing was black with oil and I initially suspected engine oil but could not find any trace of a leak on the engine. I wiped everything down and took it for a 5min drive and a fresh trace of oil formed on the bulkhead side of the gearbox case. I'm 99.9% sure it's gearbox oil as it has that "stink" to it.

Today I checked the gearbox oil by removing the horizontal filler plug. I managed to add approx 250ml before it started to come out the plug hole, so I assume that's how much has leaked in an undetermined amount of time/miles.

I removed the air filter housing etc to get a better look at the "top" of the gearbox as that's apparently where the leak is originating. I cleaned everything up and took it for another 5min drive. Fresh oil formed at the back/underside of gearbox casing again, its tracking down from higher up on the box and I THINK it's somewhere around/near the linkage mechanism but I cannot pinpoint where.

Does anyone have any suggestions of where this could be coming from? I'm guessing a seal but I can't really identify anything? I'm really struggling to see where its originating.

Some pics:

https://ibb.co/TWfXQWw https://i.ibb.co/8YC3yYm/1.jpg

https://ibb.co/kqTr12g https://i.ibb.co/P1ybQGZ/a.jpg

https://ibb.co/VwVGggG https://i.ibb.co/vX1W33W/b.jpg

https://ibb.co/ThXF8dP https://i.ibb.co/WK9YyjB/c.jpg

https://ibb.co/Q7Wqq2q https://i.ibb.co/0p0WWgW/2.jpg

https://ibb.co/XbDn7fd https://i.ibb.co/mG0n9rY/3.jpg

https://ibb.co/DLR0WYt https://i.ibb.co/0QGH2Kc/4.jpg

https://ibb.co/7rHtqCf https://i.ibb.co/kqp2tB7/5.jpg

Many thanks

[Toilet Duck]

JUST TO ADD: I'm basically trying to copy/paste from a thread I have on Pistonheads - https://www.pistonheads.com/gassing/top ... &t=1819817

[alexperkins]

We have fairly strict spam filtering on here, but it shouldnt affect your post. Ill see if I can post it for you

[alexperkins]

Not sure why that got flagged - ive reported it to our filtering provider, and put your post above

[Toilet Duck]

Not sure why that got flagged - ive reported it to our filtering provider, and put your post above

Hi Alex,

That's great, much appreciated

[Toilet Duck]

Morning all,

Still not had any luck pinpointing so far, but access is pretty tight.

I found the image below of "my" gearbox online. Does anyone know what is behind the black cover I have circled in red? I'm wondering if oil is leaking from behind that part? I can see liquid sealant between the black cover and gearbox casing. Not sure if this black cover can be removed in situ or if it's a gearbox out job?

Cheers

[alexperkins]

That’s the 5th gear cover. It can be removed in situ but drain the oil first or you’ll get covered

It could well be leaking from there. I had a look through your photos and it’s hard to see

You can see that side from looking behind the passenger wheel

[Toilet Duck]

That’s the 5th gear cover. It can be removed in situ but drain the oil first or you’ll get covered

It could well be leaking from there. I had a look through your photos and it’s hard to see

You can see that side from looking behind the passenger wheel

Many thanks.

I've had another look and I can't see anything else in that area that could be leaking oil, unless it's somehow coming out through the gear linkage point (which seems unlikely). Think I will order up a 5th gear cover seal and change that first.

Cheers