trans leak - BMW Forum

tim96 · 10-19-2009, 02:54 AM

Here are my symptons. Auto Trans fluid all over under carrige including the exhaust which causes the fluid to smoke. I wiped it all up to try and spot the source of the leak. Trans fluid is not coming from the pan/sump seal. It is coming from somewhere up above the gearbox mounts. There is also trans fluid all over the underside of my gear shifter so i guess the fluid has been flung around. Could it be from where the driveshaft eneter the gear box / trans? what is this called. Also is there anywhere else it could be coming from?

marti5 · 10-19-2009, 05:46 AM

You can check out the entire gearbox with part numbers here:

RealOEM.com Online BMW Parts Catalog

brettski · 10-19-2009, 06:15 AM

Is it possible that it could be power steering fluid and not transmission oil?

tim96 · 10-19-2009, 10:45 PM

I dont think it is the power steer rack because from the gear box mounts forward to the bonet there is no fluid at all and i dont know of any power steer lines around the gear box area. It looks like it comes from where the drive shaft comes out of the trans and goes to the diff. I will try and take some photos next time i am under there. Had a look at the diagrams but they are all facing front of the trans not the rear end of the trans. Looking at this RealOEM.com BMW E30 320i ZF 3HP22 HOUSING PARTS/OIL PAN
i would say it comes from around part no 10, it seem to drip down over the gear box mounts

marti5 · 10-20-2009, 03:50 AM

I would say its either coming out from the gasket #2 or there is a bearing/seal in #3, the only way to find out is remove that rear part#10.

tim96 · 10-23-2009, 05:58 AM

Correct me if i am wrong but you check the trans fluid with the engine at operating temperature while the car is running and on idle. And on the dipstick in the e30 there is the little ball bit at the top then a flat bit and a little ball bit at the bottom, on the flat bit there is two lines and the fluid level should be in the middle of these two lines?
Well my fluid level if i checked it right (repeated check two or three times) is above the top ball bit and above both lines.
Does this mean my trans fluid is overfilled and the "leak" is the excess fluid coming out of a overflow valve or breather or something?

marti5 · 10-23-2009, 10:11 AM

You have just answered you own question (overfilled) and all fluid levels should be checked when cold for a correct reading.

tim96 · 10-23-2009, 10:43 PM

hi, this is a photo looking through the gear shift hole to the top of the transmission. I guess the little plastic thing with the sort of washer around it above the '046' is the vent/valve? (because it looks like it). My question is .. see how the little metal disc around the plastic bit looks bent is that ment to sit flush with the trans to stop it leaking?

marti5 · 10-24-2009, 03:17 AM

You are correct that is the vent and yes that sprung washer is suppose to be like that, as its sprung to hold the vent in and allow it to open and close.

From what you have said about the level of ATF in the box, I would be draining some off or drain the lot, change the filter and fill with new to the correct level, whom ever serviced your car and put to much fluid in there in the first place doesnt seem to me to know what he is doing.....

tim96 · 10-24-2009, 03:58 PM

hey, thanks for your help. Just one thing, so are you saying the washer is ment to look bent like it is now? or is it ment to be flat?

marti5 · 10-26-2009, 09:22 AM

Bent as it is now.......its sprung, thats how it should be....

tim96 · 10-27-2009, 12:16 AM

I took the car to the oil shop to get the fluid checked. I told them i thought the auto trans was overfilled, they said it wasnt. I am sure it is..?
Here is a picture of the trans dip stick..
I thought the level was ment to be between the two lines (the red 1 and 2) and closer to 2.
Or is it between the two balls/ dots (the blue 1 and 2).
I have checked it numerous time (in park on idle, cold, warm but turned off etc etc) it is always at least the green line / the blue 2 or higher.
Is this because the trans flicks fluid up higher than the actual level when its idling or something and if your wondering yes i do wipe it clean with a rag and recheck it....same result

marti5 · 10-27-2009, 05:08 AM

If its at the green line when cold and not running there's to much in there, best thing you can do is find a download of the owners manual,at the end of the day it will just keep chucking the fluid out, which is ok but when it gets on the exhaust it will smell for ages.......get a download owners manual.

tim96 · 10-30-2009, 07:58 PM

where is the plug to drain it so i can let some fluid out?

marti5 · 10-31-2009, 03:50 AM

It will be on the bottom/side of the gearbox pan, looks like yours is at the front from the realoem link in the above post, but if you find one on the underside thats it.