Automatic gearbox losing transmission fluid
 

I have 2005 E60 525i Automatic with the N52 Engine and 6hp-19 gearbox. The car is been oily damp underneath not knowing where the oil leak is coming from, for many year now until my gearbox start slipping with “TRANSMISSION FAULT” alarms. Then I knew it was low transmission fluid.
I did went underneath to see where is the actual leak maybe it’s the oil pan. No I found the top front housing of the gearbox wet of oil from the top of the gearbox dripping to the ground.

I attached the label picture where the oil leak come from. My question is: what is is this part I labeled in the picture and what is it for? Because the transmission oil is leaking from that part not from gearbox as I did assume.
https://cimg8.ibsrv.net/gimg/5series...61db36b72.jpeg


Please assist.

Sounds like you just need your transmission serviced. That spot you have circled has nothing to do with the transmission from what I'm looking at. Maybe someone knows something I don't and they can chime in.

OP, best I can tell, that hose that you have circled is an emissions hose. It is part of the crankcase ventilation system. Now, a failed CCV system can have excessive oil in the hoses and you may even have excessive engine oil consumption -- like, do you have to add a quart regularly?

And, if it is leaking excessively from there and down to where the starter is, the crankshaft position sensor is under the starter. If that gets messed up, it can throw transmission fault codes.

I'm not saying this is definitively your problem, but it is a plausible.

Thank you for the reply I will check again, the thing is that spot I circled is in awkward space can’t reach not unless I pulled out the engine of which it’s a massive job.

thank you for sharing

I appreciate the information you supplied, at first I thought it was the engine oil pan leaking then later I thought it was a gearbox oil pan leaking. I haven’t much top up the engine oil except that the gearbox doesn’t wanna take any gears it seems like is on neutral, with the symptoms of low transmission fluid. I will google what is a CCV and see if it does not need the engine to be pulled out for it to be serviced. I do appreciate your knowledge on these engines.

kind regards,

To service the CCV, you just need to remove the intake manifold.

You may also have low transmission fluid, just that this isn't where it is coming from. If you have puddles in the garage or really suspect low transmission fluid, you can check the level. It is a bit involved to check it, so please read up on the precure first.

The most likely leak is the rubber tube seal around the electrical connector at the rear of the gearbox. The pan has to be dropped to release it from the valve body. I recently did a freshen on the box in out '06 530xi. The non xi will be easier.

I replaced the seal there and also the 5 seals above the valve body into the man trans body. Since I had the valve body out I also replaced the control solenoids, I think there are 6 of those. The transmission acts like a new one now. I got the factory parts from thectsc.com. You will need the complete serial number from the side of the transmission case to get the right ones. If you decide to do the seals, be sure absolutely no dirt of fuzz gets on the valve body.

As mentioned above, filling is quite a process and must be done properly. Read up on it, there are tons of good tutorials, including at thectsc.vom.

Thank you for your guidance, while I was stripping to access the CCV, I found that the Vent-Pipe from CCV to Cam hood was broken in to 2 pieces. That I saw the oil was coming from the broken Vent-Pipe drizzling down to the Sump (Oil pan) and Gearbox underneath, seemingly as the oil was coming from the Engine Oil pan and Gearbox oil pan, but actually it was from the CCV Vent-pipe.

I did top up the transmission fluid for the gearbox and it only took just less than a quart of oil and my gearbox is responding nicely.

Your fruitful input got the problem correct where I was getting oil leak.

THANK YOU TO EVERYONE.

https://cimg1.ibsrv.net/gimg/5series...2b09188fa.jpeg

Hi, folks, been awhile.

That #3 part circled in the above message?

If it's original, there's a 95% probability it will break as you work on moving the intake manifold for some reason (like a new starter), or if you replace your valve cover gasket.

Fair warning: buy a new one (about $50) and have it ready when you start the above jobs. Almost a certainty you'll need it. Or just replace it, because even if you get by it this time, it'll break the next time. Anyway, OP, this likely helped your Vacuum Leak condition as well, which you probabaly didn't know you had. These come in two versions, heated and unheated.

Sometimes it breaks just because it's old and a crappy plastic. Or it hates you.

#4 is the same crappy plastic, but it doesn't sit on top of the engine so lasts longer.

#2 doesn't get stressed because of it's location. so it's likely low risk.

Banglenot