[rgfinn76]

So about 6 months ago I changed my tranny fluid and installed a brand new tranny pan etc.

There have been no signs of leaks for the past couple of months... I went on vaca and the car sat for 4 days, I come back and there is tranny fluid on the garage floor.

I crawled under verified torque and cleaned it up. (It was mainly leaking on one corner of the pans) No signs of leaks after my day to day driving. So I let car sit for 3 days and starts to leak again.

Summary if I drive car everyday no leaks, if I let car sit for multiple days it seems to seep thru and start leaking.

Any ideas??? This is crazy

[limitdown]

If the transmission pan and gasket are new and the leak is coming from that area, then maybe the gasket was somehow not seated properly.
If the leak is not coming from that area, then it might be from the sealing sleeve part number 24347588725

[jkrig]

Did you replace the mechatronic sealing sleeve when you changed your fluid/pan?....If not then that could be the culprit....

[rgfinn76]

It's def not the sealing sleeve.... it's leaking from one corner of the tranny pan...I'm tempted to loosen it all up and retorque everything. But don't want to risk lossing fluid.

[STR8-6IX]

Originally Posted by rgfinn76

It's def not the sealing sleeve.... it's leaking from one corner of the tranny pan...I'm tempted to loosen it all up and retorque everything. But don't want to risk lossing fluid.

you'll probably have to retorque the bolts in the corner where it is leaking. the aluminum bolts are also one time use because they are over torqued from the factory, you may want to replace the bolts if they are original if leaking persists. you can perhaps put something underneath the transmission so you do not lose fluid or just top up when you are done.

good luck

[MysticRob]

Did you use the proper torque sequence on all 24 bolts? If not, verify not only which bolts get torqued in order, but also how much torque. I believe it's 10lb/ft + or - 1. Over-torquing can be just as bad as under-torquing since it can case the gasket to deform instead of just not seating properly. I just changed my fluid Saturday and the CTSC kit included the ZF-specific torque sequence in the box since I don't remember seeing it in the service manual I downloaded (it had the GM tranny sequence).

And above all else, make sure the mating surface is clean and that the gasket and pan itself isn't deformed, etc.

[rgfinn76]

Originally Posted by MysticRob

Did you use the proper torque sequence on all 24 bolts? If not, verify not only which bolts get torqued in order, but also how much torque. I believe it's 10lb/ft + or - 1. Over-torquing can be just as bad as under-torquing since it can case the gasket to deform instead of just not seating properly. I just changed my fluid Saturday and the CTSC kit included the ZF-specific torque sequence in the box since I don't remember seeing it in the service manual I downloaded (it had the GM tranny sequence).

And above all else, make sure the mating surface is clean and that the gasket and pan itself isn't deformed, etc.

10ft lbs? I torqued them to 10nm based on info I seen online.

[MysticRob]

Originally Posted by rgfinn76

10ft lbs? I torqued them to 10nm based on info I seen online.

Oops, I think you're right. My memory sucks, but I got the digits right, so I got that going for me.

[autoart]

10nm= 7.38ft lbs

[mweisdorfer]

The megatronic seal is famous for leaking on the E90.

The Bentley Repair manual says 7# of torque for the pan bolts. I can't imagine going over 8# since that's what the oil pan and valve cover gaskets are at.

[mweisdorfer]

The megatronic seal is famous for leaking on the E90.

The Bentley Repair manual says 7# of torque for the pan bolts. I can't imagine going over 8# since that's what the oil pan and valve cover gaskets are at.

[mweisdorfer]

The megatronic seal is famous for leaking on the E90.

The Bentley Repair manual says 7# of torque for the pan bolts. I can't imagine going over 8# since that's what the oil pan and valve cover gaskets are at.

[Wolf 335]

Originally Posted by STR8-6IX

you'll probably have to retorque the bolts in the corner where it is leaking. the aluminum bolts are also one time use because they are over torqued from the factory, you may want to replace the bolts if they are original if leaking persists. you can perhaps put something underneath the transmission so you do not lose fluid or just top up when you are done.

good luck

Over torqued from the factory?

No way that is how they do things. You have to replace them because the material is softer and they can stretch over time, or break when re-torqueing

[STR8-6IX]

Originally Posted by Wolf 335

Over torqued from the factory?

i dont think i used the right definition for this.

i meant that the OEM torque specs for the aluminum bolts are tighter then what the bolts can handle, meaning they are one time use. people on this forum recommend you replace them with each pan filter change, although i do not know if the kit comes with new bolts or not.

[MysticRob]

Originally Posted by STR8-6IX

i dont think i used the right definition for this.

i meant that the OEM torque specs for the aluminum bolts are tighter then what the bolts can handle, meaning they are one time use. people on this forum recommend you replace them with each pan filter change, although i do not know if the kit comes with new bolts or not.

10Nm is not tight be any means. There is no way the bolts can't handle that. And the reasoning behind including a few new bolts is likely because the bolt heads get stripped out after repeated use, not because of some undisclosed weakness, IMO. If this was true then I should've broken all the bolts I just retorqued to factory spec, though oddly enough none did.

[STR8-6IX]

Originally Posted by MysticRob

10Nm is not tight be any means. There is no way the bolts can't handle that. And the reasoning behind including a few new bolts is likely because the bolt heads get stripped out after repeated use, not because of some undisclosed weakness, IMO. If this was true then I should've broken all the bolts I just retorqued to factory spec, though oddly enough none did.

hmm.. I'm just repeating what i've heard elsewhere on this forum. more then one person said not to reuse the aluminum pan bolts so its good to get a second opinion on this.

[MysticRob]

Originally Posted by STR8-6IX

hmm.. I'm just repeating what i've heard elsewhere on this forum. more then one person said not to reuse the aluminum pan bolts so its good to get a second opinion on this.

No worries, I just don't see how it's even remotely possible those bolts are one-time use with only 7lb/ft being used to tighten them. Like everything else on these cars, I think the use of aluminum bolts here is strictly a weight-saving measure, not some mystical engineering reasoning to get us to buy more bolts.
If I'm wrong, someone please correct and show us all where BMW says this!