Leaking BF XR6 Turbo ZF 6 Speed

[Jonno]

I have a series 1 BF XR6 Turbo with 202,000 kms that I have owned since new. It has the ZF 6 speed gearbox, which I have had serviced about every 50,000 kms.

 

I had a general service done last week that cleared up oil leaks from the rocker cover and power steering pump and high-pressure hose. After that the engine was steam cleaned.

 

As part of that service the transmission fluid level was checked and topped up with a litre of ZF Lifeguard.

 

After parking the car in my driveway, I noticed a remaining oil leak. When I returned to the mechanic, I found that bottom front of the transmission was covered in oil (see attached image).

 

The leaking oil is darker than the engine oil which was changed at the service (see attached image).

 

My impression from driving the car is that the transmission is working as it always has. No hesitation, slipping etc.

 

Any ideas?

[Puffwagon]

My first thought is that the rocker cover was leaking oil into the bellhousing and residual oil is leaking out. If they have used a bunch of degreaser around the area after fixing the rocker cover leak, it may have also got in there, freeing up the mess inside even further. Finally the steam clean may have also leaked into the bellhousing adding to the mix. Get a mirror on a stick to have a look behind the rocker cover, it'll at least let you know if it's leaking from there still.

[k31th]

Could also be the rear main seal leaking from there... but that's unlikely if it's gearbox oil, of course... could also be a tiny leak in the converter or the seal around the input shaft/converter area... but you'd think you'd notice different driving characteristics for something like those gearbox leaks

[Puffwagon]

I hate it when my rear main seal leaks 

[Slash737]

My bf2 turbo was leaking like that.  Had the rear main seal changed, still leaking.  Turns out it was the sump leaking. Had it re sealed and it hasn't leaked since.

[Jonno]

Thanks to everyone who has commented so far.

 

If the transmission isn't leaking then how did it lose a liter of oil over the last 50,000 kms?  Do these ZF transmissions use oil?

[Puffwagon]

Maybe the trans isn't leaking, maybe they didn't fill it properly last time. No the trans won't use oil in the context of this conversation.

 

Maybe it's leaking trans fluid.

 

That's a whole bunch of mabeys based off a couple of posts and one picture.

 

You might have to do some conventional diagnosis instead of asking for forum opinions, that's how a mechanic would do it 

[Jonno]

Agreed Puff. I have visited my mechanic and a specialist transmission shop.

 

There is no agreement as to the cause or remedy. Opinions vary between a reconditioned transmission (quotes from $4.5K to $6.5K), Through to replacing front gearbox seal and rear main engine seal (about $1.5K).

 

Even at one of the transmission places, the two guys disagreed as to whether the leak was engine or transmission oil.

 

And the transmission feels like it did when it was new. So I cant understand why I would drop between $4K to $6K on a reconditioned box.

[Puffwagon]

They would be giving you a range of possible causes and fixes which is not any better than what we're doing here, except they usually know what they're on about. If it isn't coming from the rocker cover still, the sump gasket or a crack in the sump, anywhere else you can see such as turbo drain etc, or just residual, you have to pull the box out for a look. You have to pull the box to check the rear main obviously.

 

I would get under there clean the living fark out of it (perfectly clean) and have a damn good look for cracks in the sump or other possible leaking areas. After the clean and inspection, go for a short drive and have another look under there. This should show up whether it's leaking past anything external that you can see. A free way to check if it's residual is to clean it daily and see what it drops overnight. If it is residual it will eventually stop coming out. If it keeps leaking it's time to look further.

 

Reconditioning the box is not the appropriate fix for an oil leak. Would you recon an engine because it has an oil leak? You aren't reporting a trans issue, you're reporting an oil leak. It's leaking from somewhere and that somewhere needs to be found with 100% certainty before a fix is implemented.

[Dazzla_xr6]

Check ya power steering the fluid get every where did mine had no more still oil sh*t every where