What Else Should I Change When I do My Clutch?

[George Hill]

bimmerfan08 I'm a big fan of letting sleeping dogs lie on a part that is relatively easy to access.

[bimmerfan08]

You'll need a clutch alignment tool, it will come in the kit. They are hit or miss IMO. I have the BMW tool, but may not be worth it for a 1x time.

The input shaft seal, you'll need a seal driver, something long and hollow, I have a 3d printed one.

The selector shaft I use a deep socket.

The out put shaft you'll need a seal driver as a socket generally isn't deep enough for it.

George Hill, you mentioned in a prior post that you haven't seen an output shaft that's leaked. With that noted, if the back of the transmission appears dry, should I leave the seal alone? I'd rather not create a leak if one doesn't exist. Seal is original (175K miles, ~23 years).

[6speedS54]

SMG transmissions break #15 pretty regularly so I always replace that even on 6MTs. I do 9 & 17 because I don't think it could hurt. Check the roller on #8 and make sure it still turns nicely.

Mine is manual, current symptoms I have are as follows
- intermittently my shifter pops out of reverse, 1, 2, 3, less so 4th. It feels like the shifter doesn’t engage fully when I place it into gear. Some gears seem ok with that, but others pop out as soon as I release the clutch
- it could be fine for a few days sometimes a week, but then I shift and feels like the shifter doesn’t slide all the way in.
- I’ve blead the system, replaced brake fluid, replaced slave cylinder.
- I know shifter bushings are worn and clutch likely
- I don’t know if this behavior is caused by worn clutch or potentially detent springs/rollers or worst case transmission, but I doubt synchros are bad on all these gears.
- when I apply slight pressure to the clutch pedal, I feel spinning, also when in 3rd and I release the gas I feel the shifter moving.
- ChatGPT tells me there is likely clutch “drag”

I’ll order replacements you mentioned

[George Hill]

...are there any symptoms to look for or is this just preventative? Also there pins and springs on the side of the transmission and on top, are you talking about all of them?

SMG transmissions break #15 pretty regularly so I always replace that even on 6MTs. I do 9 & 17 because I don't think it could hurt. Check the roller on #8 and make sure it still turns nicely.

[bimmerfan08]

George,

you mentioned these items above, I plan on replacing my clutch soon as well, are there any symptoms to look for or is this just preventative? Also there pins and springs on the side of the transmission and on top, are you talking about all of them?

thanks

Here's a thread on the subject: https://nam3forum.com/forums/forum/m...ession-springs

This diagram and parts list from RealOEM helps, too.

i	Transmission parts for complete-repair only on request. For this repair, there is no repair-instruction or special-tool. The repair should only be made by qualified personal, at best by BMW partner organization. BMW does not assume liability and damages caused through improper repair. For vehicles with Sequential M transmission Drivelogic	S793A=No
01	Locking pin		1			23111222979	$14.67
02	Compression spring		1			23311228393	$2.80
03	Sealing Cover		2			23127527439	$4.40
04	Lock Ring	20X1	2			07119934624	$1.78
05	Locking pin		1			23311224130	$11.96
06	Compression spring		1			23111222720	$5.27
07	Torx screw, micro-encapsulated	M8X25	1			23317586637	$1.68
08	Locking pin		1			23317501584	$20.83
09	Compression spring	D=1,40	1			23317511337	$2.80
10	Thrust pin		1			23311282444	$11.49
11	Gear identification switch		1			23142229113	$89.17		+core
12	Fixing clamp		1			11787547213	$0.40
13	Tubing support		1			34521164653	$0.23
14	Ball	8G20	1			07119986280	$0.66
15	Compression spring		1			23311228405	$2.75
16	Locking device		1			23317506911	$17.11
17	Repair kit, locking		1			23317506947	$124.60
18	Hex bolt	M6X18	2			23317545769	$0.67
19	Wave washer	B6	2			23317545770	$0.78
20	Cap		1			23211222729	$6.75

https://www.realoem.com/bmw/enUS/showparts?id=BL93-USA-11-2001-E46-BMW-M3&diagId=23_0887

[6speedS54]

[QUOTE.

Your list looks pretty comprehensive. I'd consider replacing the transmission detent pins and springs too.

[/QUOTE]

George,

you mentioned these items above, I plan on replacing my clutch soon as well, are there any symptoms to look for or is this just preventative? Also there pins and springs on the side of the transmission and on top, are you talking about all of them?

thanks

[George Hill]

You'll need a clutch alignment tool, it will come in the kit. They are hit or miss IMO. I have the BMW tool, but may not be worth it for a 1x time.

The input shaft seal, you'll need a seal driver, something long and hollow, I have a 3d printed one.

The selector shaft I use a deep socket.

The out put shaft you'll need a seal driver as a socket generally isn't deep enough for it.

[bimmerfan08]

I've had really good luck with LuK TOBs, that is what I always use. I do replace the pilot bearings with new BMW not from the LuK clutch kit.

I'm with Ian, you could make a case for replacing the input shaft seal while you are in there. And likely the selector shaft seal is leaking but I can't remember the last time (if ever?) that I've seen an output shaft seal leaking. If you replace the input shaft seal DO NOT drain the transmission oil before removing the trans, leave it filled. Replace your input shaft seal and then stand the transmission vertically on with the bell housing surface on against the ground. If it doesn't leak overnight it likely won't leak in the car, just a quick test to make sure you installed the seal correctly.

Your list looks pretty comprehensive. I'd consider replacing the transmission detent pins and springs too.

Guibo bolts, never seen one fail on its own, I'd run them.

Bushing for the front of the driveshaft, I haven't seen one fail either.

The 668 exhaust gaskets are GARBAGE from HJS, BMW only.

I'd consider BMW for the RMS stuff as well.

Thanks for the suggestions, George.

Are any special tools or methods needed to replace the seals and bearings in discussion?

[George Hill]

I've had really good luck with LuK TOBs, that is what I always use. I do replace the pilot bearings with new BMW not from the LuK clutch kit.

I'm with Ian, you could make a case for replacing the input shaft seal while you are in there. And likely the selector shaft seal is leaking but I can't remember the last time (if ever?) that I've seen an output shaft seal leaking. If you replace the input shaft seal DO NOT drain the transmission oil before removing the trans, leave it filled. Replace your input shaft seal and then stand the transmission vertically on with the bell housing surface on against the ground. If it doesn't leak overnight it likely won't leak in the car, just a quick test to make sure you installed the seal correctly.

Your list looks pretty comprehensive. I'd consider replacing the transmission detent pins and springs too.

Guibo bolts, never seen one fail on its own, I'd run them.

Bushing for the front of the driveshaft, I haven't seen one fail either.

The 668 exhaust gaskets are GARBAGE from HJS, BMW only.

I'd consider BMW for the RMS stuff as well.

[nextelbuddy]

From my understanding the big difference between the OE sachs throwout bearing and the luk throwout bearing that comes with the clutch kit is that the luk throwout bearing is built a little bit differently. It rattles when you shake it. When I talked to George Hill If I remember correctly he informed me that those throw out bearings were built that way because they were made to handle movement and the throw out bearing if something got off center or off axis compared to the sachs and BMW units that were fixed. The luk was meant to take up any "slop" in the throw out action

I could be wrong though. Maybe he can shed some more light on it

Basically luk knows what they were doing when they manufactured their throw out bearing the way that they did

[bimmerfan08]

Because of the amount of effort involved for things that require the trans to come out, I'd limit myself to OE BMW for...
Rear main seal
Throw out bearing
pilot bearing

Unless the slave/master cylinder is leaking, or your having been bleeding it over the years, I don't see any reason to replace it. You can do it later without pulling all that stuff out, so not really a ton of work if it ends up being a mistake.

More controversially... 420g doesn't seem to be that leaky. Unless you have a leak you're looking to address, I might be inclined to leave its seals alone.

I'd do new stock for the selector rod joint, but that's more of a preference.

Pretty sure my flex disk bolts are original-- are they supposed to be one time use?

Thanks for the advice, Ian. Regarding the flex disk bolts, I don't recall if they're reusable (I think so?). The original post in this thread had them being replaced, but I need to verify before buying. I recall them being non-TTY bolts when I dropped the driveshaft to reinforce the RACP years ago.

[bimmerfan08]

Perhaps consider a OE (or Sachs) throwout bearing. The Luk unit that came with the clutch kit, while I'm sure is fine, seemed "less substantial" than the OE BMW piece (I'm not sure how else to describe it). It rattled more when just handling and shaking by hand. If I remember correctly it lacked the "cage" around it. The Sachs unit seems to have it, and looks like the OE piece. I'm not sure what difference it make, though.

Thanks. After going back through the thread, that seems to be the consensus.

[Obioban]

Because of the amount of effort involved for things that require the trans to come out, I'd limit myself to OE BMW for...
Rear main seal
Throw out bearing
pilot bearing

Unless the slave/master cylinder is leaking, or your having been bleeding it over the years, I don't see any reason to replace it. You can do it later without pulling all that stuff out, so not really a ton of work if it ends up being a mistake.

More controversially... 420g doesn't seem to be that leaky. Unless you have a leak you're looking to address, I might be inclined to leave its seals alone.

I'd do new stock for the selector rod joint, but that's more of a preference.

Pretty sure my flex disk bolts are original-- are they supposed to be one time use?

[Will]

Perhaps consider a OE (or Sachs) throwout bearing. The Luk unit that came with the clutch kit, while I'm sure is fine, seemed "less substantial" than the OE BMW piece (I'm not sure how else to describe it). It rattled more when just handling and shaking by hand. If I remember correctly it lacked the "cage" around it. The Sachs unit seems to have it, and looks like the OE piece. I'm not sure what difference it make, though.

[bimmerfan08]

Spring clip need replacing, too?

21517570284

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