Transmission leaking oil at case joints

[cobra]

Kind of a shot in the dark here, but while doing some routine maintenance I noticed my transmission was covered in oil. I assumed it was a leaky drain plug that just wicked everywhere so I cleaned everything up, used some thread sealant on the plugs, and filled with ~2L of new fluid. Lo and behold, I can see fluid accumulating again at the joints where the transmission is bolted together.

I can't see a clear definite starting point, it just looks evenly distributed across the gasketed area and pools at the bottom where the red arrows are.

Has anyone heard of this? I don't think it's losing enough to cause an issue with low fluid level, but is just kind of annoying that it attracts dirt over time and I would like to fix it if that's even feasible.

Thanks

Pic below of the before I touched anything.


And after cleaning


After cleaning (side view)

[nextelbuddy]

I have the same exact problem. Never actually drips in the floor but I always find accumulation in those 2 spots whenever I'm under the car.

[Anri]

Hi Cobra,

Its time for Re-Seal. These cars are 15 years+ old.

When I do SMG to Manual I always split the cases and
re-seal them. The BMW compound does not last forever.

Regards,
Anri

[cobra]

Hi Cobra,

Its time for Re-Seal. These cars are 15 years+ old.

When I do SMG to Manual I always split the cases and
re-seal them. The BMW compound does not last forever.

Regards,
Anri

Interesting! Can you provide some details on how you do this job? Is it possible to disassemble easily or is there a special process/tools involved? When I have my transmission out I will do it.

Thank you

[sapote]

OP, is this original stock tranny or SMG converted? I would guess the factory sealant do not leak even after 15 years if not opened up.

[cobra]

OP, is this original stock tranny or SMG converted? I would guess the factory sealant do not leak even after 15 years if not opened up.

Original stock manual tranny.

[mrgizmo04]

Permatex anaerobic sealant (believe it is red) works well for this. Remove the bolts, gently pry the two pieces apart (you only need like 1/4" of space), and apply the sealant.

Sent from my SM-G950U using Tapatalk

[cobra]

Permatex anaerobic sealant (believe it is red) works well for this. Remove the bolts, gently pry the two pieces apart (you only need like 1/4" of space), and apply the sealant.

Sent from my SM-G950U using Tapatalk

Do I run the risk of a spring popping out or some weird thing by doing this? I'm a bit afraid to pull it apart tbh.

[Anri]

Interesting! Can you provide some details on how you do this job? Is it possible to disassemble easily or is there a special process/tools involved? When I have my transmission out I will do it.

Thank you

Cobra,

If not mistaken, I can tell you have not done this Challenge.
No special tools are required, but rather experience.


You have 2 options.



A) Get jack stands from the local store. Start reading some
of the DIY as much as possible. Then dive bomb in the job.

Taking the box is easy part, right at when you see the box
next to the car you are let me pop a beer I did it..yahoo I
just did it.

DIY Papers on the table of how to removed the box cases...
and right when you juuuust about to spit the bell out of the
second mid piece oh shiiit the input shaft bearing plastic cage
juuuust broke...ohhhh fuuuuuuuck...JB weld comes to mind....
or one selling G420 for parts...okay you get a bearing
replacement..Good start, but we are not done yet....

DYI papers "Step by Step" are detailed but not enough. So
somehow you just happen to randomly have all the cases
apart, None drying paste/compound from BMW is about $80
or something I forgot...then on the way back it will be a lot of
fun..


So say somehow you manage to assemble it together, and
a week later worth of work between 8pm and 12pm of bloody
work on the ground you are ready to make the local first test
drive....1st, 2nd, 3rd...all nice and smooth but say 5th and 6th
are not engaging........ohh fuuuuck what happen...........then
all over again till its all as factory but it may take few times etc.

B) Find a shop that works on these cars on daily basis and
they have done this job many times...drop the car after work

Go back home at 8pm, open a nice Napa Red Wine and get
some cheese on the plate and enjoy life. 3 days later the shop
calls you for pick up.


Which option do you prefer ? Whichever option you take
I support it 100%



Regards,
Anri.

[cobra]

Cobra,

If not mistaken, I can tell you have not done this Challenge.
No special tools are required, but rather experience.


You have 2 options.



A) Get jack stands from the local store. Start reading some
of the DIY as much as possible. Then dive bomb in the job.

Taking the box is easy part, right at when you see the box
next to the car you are let me pop a beer I did it..yahoo I
just did it.

DIY Papers on the table of how to removed the box cases...
and right when you juuuust about to spit the bell out of the
second mid piece oh shiiit the input shaft bearing plastic cage
juuuust broke...ohhhh fuuuuuuuck...JB weld comes to mind....
or one selling G420 for parts...okay you get a bearing
replacement..Good start, but we are not done yet....

DYI papers "Step by Step" are detailed but not enough. So
somehow you just happen to randomly have all the cases
apart, None drying paste/compound from BMW is about $80
or something I forgot...then on the way back it will be a lot of
fun..


So say somehow you manage to assemble it together, and
a week later worth of work between 8pm and 12pm of bloody
work on the ground you are ready to make the local first test
drive....1st, 2nd, 3rd...all nice and smooth but say 5th and 6th
are not engaging........ohh fuuuuck what happen...........then
all over again till its all as factory but it may take few times etc.

B) Find a shop that works on these cars on daily basis and
they have done this job many times...drop the car after work

Go back home at 8pm, open a nice Napa Red Wine and get
some cheese on the plate and enjoy life. 3 days later the shop
calls you for pick up.


Which option do you prefer ? Whichever option you take
I support it 100%



Regards,
Anri.

Haha those are great options.

I am very mechanically inclined. Have rebuilt several engines from the ground up. Always prefer the DIY option! I don't trust most shops!

So you got any specific tips?

[Anri]

Haha those are great options.

I am very mechanically inclined. Have rebuilt several engines from the ground up. Always prefer the DIY option! I don't trust most shops!

So you got any specific tips?

Be very careful how you take the bell out. Press is your best
and safest way but not sure if you have one ?

Then the challenge begins...

I don't know were to start and honestly if describe
how to do the job from the beginning to the end my post will
look like prescription drug from the Hospital....

Check some DIY and as you say you are technically inclined
you should get the idea and then you will get on the fly.

Regards,
Anri.

[sapote]

Open up the bellhousing is normal (watch out the 4 small bearing and washer on the main shift rod falling out, and so it's best to stand the whole thing up with the bell facing ground, then pull the tranny half up so the falling small parts not get into the gears and gut). The tricky part is open up the other half: cannot be done until the inter-locking detent pins are remove (inter-locking mechanism is used to prevent multiple engaged gears), which are near the very rear of the box.

[nextelbuddy]

OP, any updates on this? I'm about to pull my transmission for a twin disc clutch job. So while it's out, I planned on separating the bell housing to reseal it or something like Honda Bond or the like.

On mine I'm also wondering if it's leaking from the input shaft seal. I'm not sure if a leak from the input shaft seal would show itself as a leak between the casing.

In my case I already purchased a brand new input shaft seal and all the parts associated with the clutch job like the guide tube etc and all those parts.

[tlow98]

The first joint at the bellhousing isn’t too bad. It’s the same for every smg to manual swap, just don’t pull it all the way. Like Gizmo said, 1/4” is fine. The pieces that fall out won’t fall out until the bell housing is about 2” out.

the other joint… no idea. Not much info out there on that one!

[0-60motorsports]

Have the same issue. Will address it If i ever do a clutch job.