Bell housing leak recommendations

[bavarian3]

I understand the bellhousing leaking isn't a rare issue from what I've searched on the forum. Most of what I've read involved the drain plug and seams which mine is weeping from as well... but after thoroughly cleaning and running the car the quickest to show leaking is from the actual joining bolts(pic below shows green leak).

What does everyone recommend here? Only thing I can think is pull(if safe to do so) the leaky bolts and add Gasoila thread sealant as I saw recommended in another thread.

Side note: As you see apparently pentosin(or all trans fluid?) shines green under the black light. I accidentally discovered this when inspecting for engine oil(with dye added) leaks.

[Slideways]

Unless it is actively leaking drops on to the floor, I'd leave it alone until the transmission needs to be pulled for something else. At that point, it can be resealed.

[bavarian3]

Unless it is actively leaking drops on to the floor, I'd leave it alone until the transmission needs to be pulled for something else. At that point, it can be resealed.

it's leaking pretty good. the seams are just a weep that i can deal with but the screws and drain plug are creating actual drops.

[Slideways]

it's leaking pretty good. the seams are just a weep that i can deal with but the screws and drain plug are creating actual drops.

You could use Permatex thread sealant on the drain plug as I saw it recommended by the M539 guy. Possibly on those two case bolts as well.

[sapote]

but after thoroughly cleaning and running the car the quickest to show leaking is from the actual joining bolts(pic below shows green leak).

the bolt should not leak if the gasket sealer on the joint is good. I would loosen it half a turn, then torque it to spec again and hopefully the sealer is compressed properly and stop the leak.

For the drain bolt, don't try to torque it a liitle more as it has pipe threads and can crack the case. Remove and wrap some blumping teflon tape on the threads and install again.

[bavarian3]

the bolt should not leak if the gasket sealer on the joint is good. I would loosen it half a turn, then torque it to spec again and hopefully the sealer is compressed properly and stop the leak.

For the drain bolt, don't try to torque it a liitle more as it has pipe threads and can crack the case. Remove and wrap some blumping teflon tape on the threads and install again.

Thanks I can try this. Do these seem like the right bolts. Any risk in pulling the bolts one by one and applying some sealant?

[sapote]

M12 76Nm or 56ftlbs sounds a little high to me, but It's M12 so I guess it's correct. Search some more to make sure as I would be a bit worry about 56 ftlbs on aluminum threads.

[bigjae46]

Shouldn’t those bolts be an e-torx head?

The torque value should be a little lower since the trans case is cast aluminum. I’d maybe try pulling the bolt, apply thread sealer, clean the hole really well and blow it out (hahaha) and then re-torque the bolt.

[sapote]

Any risk in pulling the bolts one by one and applying some sealant?

These bolts should be torqued in sequence gradually. I don't think adding sealant on bolt threads will help as the case sealant is what stops the oil leak, not the bolt threads.

[bmwfnatic]

The bolts on the transmission are M8, they are pretty small, when I went to reseal my transmission I paint marked them before loosening them a quarter turn, then used the digital torque wrench to see the torque required to line them back up, it’s 18-19nm.

[bavarian3]

The bolts on the transmission are M8, they are pretty small, when I went to reseal my transmission I paint marked them before loosening them a quarter turn, then used the digital torque wrench to see the torque required to line them back up, it’s 18-19nm.

good move, thanks for this info.

[sapote]

The bolts on the transmission are M8, they are pretty small, when I went to reseal my transmission I paint marked them before loosening them a quarter turn, then used the digital torque wrench to see the torque required to line them back up, it’s 18-19nm.

So which bolts are the M12 as I saw on the part list?

[bmwfnatic]

So which bolts are the M12 as I saw on the part list?

None, not all specs are for the E46, probably for another vehicle.

[sapote]

None, not all specs are for the E46, probably for another vehicle.

RealOEM doesn't show the bolts holding the bell-housing or the rear housing since BMW don't allow repair for these boxes.

That's why I thought 56 ftlbs was high for these bolts. Good catch to avoid stripping the threads.

[sapote]

Someone should revisit the Torque Specification file and correct it.