[Efthreeoh]

This is a DIY for removal and replacement of the manual transmission clutch for the E90 with the N52 engine. The procedure for the N54/55 is mostly the same except maybe for the transmission mounting bolts. This DIY is for experienced home mechanics with a decent set of quality tools. If you are a novice at car repair, the scope of a clutch replacement is probably beyond your skill set and tool kit. The use of air impact tools is highly recommended for some procedures. I used a two-post automotive lift to do this work. The rear main seal requires use of special tools and sealants (only available from BMW). I ended up not needing to replace the rear seal, but I provide the procedure I was going to use to replace it. The Bentley repair manual goes into great detail on how to remove and replace the seal, so I highly suggest you use the Bentley for the rear seal. I sourced most my parts from Turner Motorsports. They were very helpful. If you buy from Turner, make sure you get the correct flywheel. Their website lists the flywheel for the 2006 E46 325ci, not the E90 N52. If you plug in the E90 flywheel part number from realoem.com, turner has the correct part.

I do recommend you use the Bentley repair manual as reference with this DIY. This DIY attempts to “fill in the gaps” where the Bentley has no information.

The attached Adobe is 19 pages long. There is a lot of detail to go over. A few guys have done the clutch on jackstands, but I can't see doing it on stands; getting to the top bell housing bolts is a PIA. On stands you'd have to have a helper sight-in the tools to get to the bolt heads.

If your oil pan gasket is leaking, I highly recommend doing the pan gasket before or just after the clutch. The rear of the oil pan protrudes into the bell housing behind the flywheel. The clutch pressure plate has cooling fins built into it that make enough airflow in the bell housing to spread engine oil all over the place; it makes a serious mess.

There is much debate about replacing a non-leaking rear main crankshaft seal. The several professional mechanics I know all say if the rear seal is not leaking, regardless of mileage, then leave it in place and do not replace it. The thought here is if you replace the seal, there is a 50/50 chance the new seal may develop a leak. With the N52, the seal requires special tools for removal and installation. I could not locate the tools on line anywhere (in late 2015). I'm sure you can rig some special tools and replace the seal, but if the seal is not leaking, I recommend leaving it alone. Also, the seal needs special sealants and primer chemicals to correctly install it. The products are from Loctite, but their website does not list them. I found the primer and sealant is only available from BMW and costs about $80 for the kit.

Finally, my car had a driveline vibration related to engine RPM. At high RPM it made an awful noise and vibration. At idle the vibration made for a lumpy idle that kind of feels like a constant misfire. I confirmed the vibration was the dual-mass flywheel being bad, which is why I was replacing it. So if your car has RPM related vibrations and no SES light, it is probably the flywheel. BAV Auto has a few articles on the issue (I discovered later) that indicates the dual-mass flywheel can indeed go bad and cause vibration. There are single-mass flywheels that you can replace the dual-mass with, but I wanted to remain stock. I've read where the single-mass units up the engine power a bit because they are significantly lighter than the stock dual-mass unit, but the tradeoff is driveline vibration, which is what I was chasing down to solve.

I hope this DIY saves you time.

[driverman]

Great write-up. Thanks for posting.

[prelude2perfect]

Awesome write-up! I've done the clutch on the N54 3 times now and even I learned a couple things from your write up, thanks. I'll be doing my 4th job later this week and am happy to see a better way to get to that top bell housing bolt! That thing is a royal PITA

[Efthreeoh]

Originally Posted by prelude2perfect

Awesome write-up! I've done the clutch on the N54 3 times now and even I learned a couple things from your write up, thanks. I'll be doing my 4th job later this week and am happy to see a better way to get to that top bell housing bolt! That thing is a royal PITA

I can't speak to the N54, but on the N52 jacking up the front of the engine another 3 inches made all the difference in getting to the top 3 bell housing bolts. Making long guide pins out of the old E18 bolts was key to getting the trans aligned with the block. I wish I had thought of just grinding the head diameter down rather then cutting the heads off.

[Awenthomas]

Hi Efthreeoh,
Great write up about the clutch replacement N52. The information that you provide will be very useful.
Thanks!!

[roundle]

Great post.

My flywheel vibrates upon deceleration (4600 - 4200 RPM).

Did you perform a postmortem on your old dual mass flywheel? What component failed?

[Efthreeoh]

Originally Posted by roundle

Great post.

My flywheel vibrates upon deceleration (4600 - 4200 RPM).

Did you perform a postmortem on your old dual mass flywheel? What component failed?

Not yet; it's still on my bench awaiting dissection.

[itb76]

Thanks a bunch for posting this, it is a very comprehensive writeup. I did this on a 2006 330xi due to the failure of the dual mass flywheel. My comments are as follows.

Obviously a lift is preferred, but this job is doable with jack stands and a low rise transmission jack. The "bitch clips" swivel but don't want to slide out, in this case remove the shifter from inside the car. The transfer case makes the transmission really heavy in the rear.

I'm extremely thankful that you suggested tilting the engine with a floor jack, this job would have been a struggle without.

Finally, it's a good thing you didn't torque the E18 bolts to 73 ft-lbs. The Bentley says 72 Nm = 53 ft-lbs for these, 32 ft-lbs for the E12 bolt and 16 ft-lbs for the E10 bolts. The E14 steel bolts also get 53 ft-lbs.

[wdb]

Adding a kudo to the list of kudos. I'm doing an S54 in a Z4M but this answered a few of my questions even so. Thanks!

[juld0zer]

It is also important to inspect the new clutch cover prior to installing. Wipe the pressure plate with a lint free rag and brake cleaner.

Most importantly, these are self adjusting clutches. Check the springs. I have seen it several times now where the mechanism has loosened in transit/handling despite the ninja start lock correctly installed. The springs should all be compressed, otherwise they are in the 'worn' position.
Maybe the factory didn't fully retract the mechanism?
You will need to follow the steps to reset an SAC. Special tools are required for this. Videos exist on Youtube. There are also several alternative methods and universal tools available.

[850CSi]

A couple of dumb questions as I get ready to start this project.

First, I assume there's no need to drain the engine oil in advance if I'm not planning to prophylactically replace the crank seal/RMS? (I plan on leaving it alone unless it's visibly leaking)

Also, is it best to have the transmission in neutral or leave it in gear in advance? I imagine the latter would make it easier to line things up on the way back in?

[Efthreeoh]

Originally Posted by 850CSi

A couple of dumb questions as I get ready to start this project.

First, I assume there's no need to drain the engine oil in advance if I'm not planning to prophylactically replace the crank seal/RMS? (I plan on leaving it alone unless it's visibly leaking)

Also, is it best to have the transmission in neutral or leave it in gear in advance? I imagine the latter would make it easier to line things up on the way back in?

No need to drain the engine oil, the crank seal is well above the top of the oil level in the oil pan.

Yes leave the trans in neutral. If you leave it in gear, no worry it just means you may need to move the output shaft to get the splines lined up.

If you've not finished sourcing the parts, I'd get a new shift shaft seal. Mine was leaking, and it's leaking a gain. It's easy to get the shift shaft seal out when the trans is out. If you are considering a short shift kit, now is the time to install it when the trans is out of the way.

And make sure you get a new throw out bearing sleeve!

Get all 4 wheels off the ground.

[850CSi]

Got it, thanks! Fingers crossed I don't find a leaky RMS because I'm not sure what I'd do at that point...

I'll be on a kwik lift, so all four wheels off the ground around 20". Not as good as a two or four post lift, but perhaps better than jackstands.

I'm refreshing my shifter and putting in the BMW SSK. With respect to the shift shaft seal you're talking of, you're referring to part no. 23128677736?


Also, your DIY references a dowel -- part no 11217516681. I can't figure out what that's for. Do you recall?

Also, the Bentley manual is telling me the wheels need to be off the ground for driveshaft removal. I can't understand why that would be necessary -- am I missing something?

[wdb]

Originally Posted by 850CSi

Also, the Bentley manual is telling me the wheels need to be off the ground for driveshaft removal. I can't understand why that would be necessary -- am I missing something?

Perhaps to allow for driveshaft rotation?

[Efthreeoh]

Originally Posted by 850CSi

Got it, thanks! Fingers crossed I don't find a leaky RMS because I'm not sure what I'd do at that point...

I'll be on a kwik lift, so all four wheels off the ground around 20". Not as good as a two or four post lift, but perhaps better than jackstands.

I'm refreshing my shifter and putting in the BMW SSK. With respect to the shift shaft seal you're talking of, you're referring to part no. 23128677736?


Also, your DIY references a dowel -- part no 11217516681. I can't figure out what that's for. Do you recall?

Also, the Bentley manual is telling me the wheels need to be off the ground for driveshaft removal. I can't understand why that would be necessary -- am I missing something?

There is a dowel that indexes the flywheel to the crankshaft so the bolt holes in the flywheel line up with the bolt holes on the crankshaft. I bought an extra one just in case the one on the engine was damaged.

Yes, the shift shaft seal P/N 23128677736

[Efthreeoh]

Originally Posted by wdb

Perhaps to allow for driveshaft rotation?

Yes. The 4 bolts that affix the rear of the driveshaft to the diff are all not accessible with the driveshaft in a static position; you have to rotate it to get to all of them.

[850CSi]

Thank you both. That's what I figured. Just wanted to make sure it wasn't a matter of stressing the driveshaft or diff or damaging the axles etc in some way. I'm using a kwik lift (basically a giant set of ramps), but I have a bridge I can use to lift the wheels up off the ramps at least temporarily to rotate the joint.

...Here we go! In addition to the flywheel/clutch and rebuilding the shifter, I'll be doing a 3IM swap and renewing my CCV system. Very excited to get my car back after several years of steady deterioration and hopefully won't screw this up.

[Efthreeoh]

Originally Posted by 850CSi

Thank you both. That's what I figured. Just wanted to make sure it wasn't a matter of stressing the driveshaft or diff or damaging the axles etc in some way. I'm using a kwik lift (basically a giant set of ramps), but I have a bridge I can use to lift the wheels up off the ramps at least temporarily to rotate the joint.

...Here we go! In addition to the flywheel/clutch and rebuilding the shifter, I'll be doing a 3IM swap and renewing my CCV system. Very excited to get my car back after several years of steady deterioration and hopefully won't screw this up.

Just take your time. I have tips on the intake/CCV removal install too.

1 - Write down the purpose, (gasket) color, shape, and pin-count of every electrical connector. Make a check list while unplugging the connectors, it really helps upon reassembly.
2- Make a drawing of of the junction box for the CCV.
3- Remove the alternator (it'll cost you new bolts). Having the alternator out REALLY helps putting the intake manifold back in.
4- remove the PS reservoir and the bracket from the fender and move it out of the way.
5- connect the valve cover vent tube to the CCV catch can side first. Make the connection to the valve cover the last connection of the tubes in sequence.
6- connect the oil drain tube electrically and leave it hanging. Reconnect it to the oil pan then to the CCV can from underneath the car. Remove the sheet metal guard for the fuel lines on the left frame rail, which gives all the room needed to connect the oil return drain line.
7- be prepared for the hardest thing to remove will be the electrical junction box on the bottom of the manifold. The metal bracket will be RIP (rusted in place) to the plastic manifold.
8- try not to cuss too loud.

[850CSi]

Thank you! That's extremely helpful.

The pelican parts DIY makes it sound like total removal of the driveshaft (and others have suggested, the exhaust) isn't necessary. Is there enough room to get the transmission out in that scenario?

https://www.pelicanparts.com/BMW/tec..._Replacing.htm

[Efthreeoh]

Originally Posted by 850CSi

Thank you! That's extremely helpful.

The pelican parts DIY makes it sound like total removal of the driveshaft (and others have suggested, the exhaust) isn't necessary. Is there enough room to get the transmission out in that scenario?

https://www.pelicanparts.com/BMW/tec..._Replacing.htm

There is no way you can get the trans out without removing the exhaust. Removing the drive shaft is 4 extra bolts. Get it all out of the way.

[wdb]

Originally Posted by Efthreeoh

8- try not to cuss too loud.

Eh. Macht nichts.

[850CSi]

There was definitely some profanity getting the manifold out...

So, here's where I'm [not surprisingly] stuck now. I don't think I can get a grip on these -- the whole assembly is crumbling.



I am reading that my only real option is to angle grind/cut the bolts and studs off together, flush with the surface of the rear-side flange and pull the exhaust out? Ideally I'd then be able to drill the rest of the studs out and replace with new bolts/nuts?

Problem is, I don't think I have anything powerful enough to drill that stud out. And I'm not even sure I'd be able to cut the top side nut/studs.

Better perhaps to just cut the midpipe and then clamp it back together?

Probably should've taken it to an exhaust shop beforehand...