Rear Main Seal

[Blackjetvette97]

Hi all,
Has anyone done this job of replacing their seal?? I'm coming about due for mine. I would just like to know what is involved(and what else I should tackle while in there) to swap it out. My mechanic is wondering if the starter bolts are both accessible from one side or are facing opposite directions thus requiring exhaust removal(I think that's what he was wondering about, anyway, from what I can remember). Any help or advice would be appreciated. Also, what parts will I need to do the job thoroughly and effectively?? Is there a DIY on here or on utube or anywhere else possibly, to get an idea of the task? Thanks


Steve

[Roman D]

Hi, all bolts are accessible from transmission side.
Both driveshafts need to be disconnected, rear unbolts from transfer case side and and be left hanging with some kind of support, front one unbolts from differential side and can be left on transfer case that also have to come off, after removal of all of bellhousing bolts (2 of them holding starter) transmission can be removed and rear seal is right behind flywheel.. BMW recommends most of those bolts to be used only once, especially on flywheel so order some.. Check your flex disks, make sure they're good otherwise order new ones. Also, somewhere on this forum I've read that sometimes valve cover gasket leaks at the rear and oil finds its way in to bell housing and drips at the bottom of it looking just like it is a bad rear crankshaft seal, make sure it is not your case because this is a descent size job to do or pay for and then you will wind up changing valve cover gaskets anyway.

[Roman D]

There are 2 bolts and guide pin, nothing else that holds the starter.. I had spent a quite a bit of a time separating them as a pin got oxidized and did not want to let go. Google x5 e53 bell housing, click "images" and there will be number of pictures showing bolts etc.

[Blackjetvette97]

Roman, Thank you for the input and information....appreciate it!

[richardb]

Originally Posted by Roman D

Hi, all bolts are accessible from transmission side.
Both driveshafts need to be disconnected, rear unbolts from transfer case side and and be left hanging with some kind of support, front one unbolts from differential side and can be left on transfer case that also have to come off, after removal of all of bellhousing bolts (2 of them holding starter) transmission can be removed and rear seal is right behind flywheel.. BMW recommends most of those bolts to be used only once, especially on flywheel so order some.. Check your flex disks, make sure they're good otherwise order new ones. Also, somewhere on this forum I've read that sometimes valve cover gasket leaks at the rear and oil finds its way in to bell housing and drips at the bottom of it looking just like it is a bad rear crankshaft seal, make sure it is not your case because this is a descent size job to do or pay for and then you will wind up changing valve cover gaskets anyway.

Sold advice here!

[Roman D]

Sold or solid? He-he.

[jfoj]

Make sure you do not have crankcase air leaks.

Lack of enough crankcase vacuum can cause some of the seals to leak easier.

Also do not rule out the Oil Filter Housing Gasket (OFHG) as a source of a leak that can cause oil to look like it may be leaking from other locations.