6-speed won’t go into 5th or 6th after new clutch install

[01CT540i]

Hi all,

I just completed installing a new clutch in my 01 540i. It shifts great going into reverse and 1st through 4th but won’t go into 5th or 6th without grinding. I had to replace the slave cylinder because I damaged it during removal or install of the transmission. I installed a stock style clutch kit with flywheel and replaced the pilot bearing and transmission seals that came in the Bavauto install kit.

I attempted to bleed the hydraulics several times both with a pressure bleeder and also reverse bleeding from under the car with no effect.

I’m confounded! I’m wondering now if I somehow damaged the syncro can’t think of how? I am not aware of any shift linkage adjustments I can make.

This car has not been abused and hasn’t had any transmission issues before. Its a summer commuter car. It’s stock except for an aftermarket shifter installed at about 40k miles. It has 127k now.

Any thoughts or advice?

Thanks!

[bmwdirtracer]

I'd guess that the shifter selector rod is in backwards, or from the wrong side.

part 4:
https://www.realoem.com/bmw/enUS/sho...diagId=25_0009

[RSnider]

Just a tiny bit of air in the system can absolutely cause worn synchros to start grinding. I know you said you bled the clutch multiple times but you also mentioned you had to replace the slave cylinder; It can sometimes be really tricky to get every last bubble out of the system after replacing either the master or slave cylinder, especially if you didn't do a bench bleed before installing it. Just keep at it and drive the car between bleedings to help dislodge any stubborn bubbles.

This is important: You don't want to be switching back and forth between pressure bleeding and reverse bleeding because if you've been working a bubble through the system but it isn't out yet and you change bleed methods, now you're sending the bubble back the other way. Choose whichever method is easiest for you and stick with that.

The only concern I have is that it's grinding only 5th and 6th. Worn synchros typically first appear on 2nd or 3rd because they get the most abuse but it is possible for higher gears to wear out first if your driving habits have you shifting between 5th and 6th more than any other gears.

Out of curiosity, how did you damage the slave cylinder? Is it possible you also damaged something else? The first thing that comes to mind is the shift linkage. If the shift linkage got bent or, as bmwdirtracer mentioned, installed incorrectly, that can also lead to issues with shifting.

One last thing to consider: some short shift kits are notorious for putting extra strain on the synchros and wearing them out prematurely in addition to making it just generally harder to shift. You might put the stock shifter back in and see if anything improves.

[01CT540i]

Success!!! bmwdirtracer you nailed it! I was thrilled to find that I installed the linkage on the wrong side (and wrong ended)! I swapped it around and just got back from a test drive and it works like a charm! Shifts smooth and into every gear just like from the factory. I can't tell you how relieved I am to have this sorted! In fact, its just luck that it I didn't install it so that it would rub on the flex disk. It has a curved end that obviously is intended to clear the disk (well, obvious now anyways).

This was more than a month long project for me. I don't have much time to dedicate to car service and its the first clutch I've serviced in more that thirty years. I needed to do this job for at least the last 10k miles. I've had to take much care driving this thing to keep it from slipping and, you know, its a 540 so that's no fun! It was a challenge and I did it 99% by myself. I'm so happy to have the service of this website to help me along!

To fill in RSnider on why the slave cylinder got damaged, its a bit of a story I'll share for laughs: I had left it connected to the hydraulic line while removing and installing the transmission. It must have gotten tweaked as I was wrestling with the trans. When I got to the point where I wanted to give the clutch a test, I installed the slave cylinder and went up top to push in the pedal. When I did, the pedal went straight to the floor with no resistance and made a little "sprang" noise. I'm not an expert but I know enough to realize that neither of those things is

ever

good! I went back under and pulled the slave cylinder out to find it had puked its guts into the bell housing -including the fluid. After a panicked vision of having to pull the trans out again, I got to work fishing for the parts through the 1.5 inch hole. Luckily I was able to collect everything. Of course I had to do something about the fluid so I soaked it up with shop towels tied to coat hanger wire stuffed through the hole. It eventually came up dry. I shined a light in the hole to see if the fluid got onto the clutch itself and I didn't see any evidence of that. The lever seems to have shielded it from spraying that way. Whew!

I was able to put the slave cylinder back together (its held together with a toothed wave washer). But, I ordered a new one regardless. When the new part arrived I read up on the install and bleeding procedure in the Bentley manual. I build a tool to compress the pin/piston out of threaded rod and a piece of press board. I hooked up the slave cylinder to the fluid line and compressed the piston into cylinder housing. I pumped up the pressure bleeder to 15 psi then I had the flawed idea to push in the pedal again (this is not written in the procedure). When I went back under the car I found the tool broke and the boot was blown up like a balloon with the push pin just hanging on... I jumped out from under the car to relieve the pressure but was too late! I heard to boot burst and fluid spray everywhere. I cried for a few minutes, eventually pulled myself back together, and decided to hook up the old slave cylinder and start over. This is where my original post began.

Thanks a lot to both of you for your knowledge and advice. I hope to pay it forward sometime!

[bmwdirtracer]

And now you know why I use a marker on that selector rod to mark front/rear, and direction. I learned my lesson the hard way, same as you.

I've also learned the hard way about bleeding a slave. Now I do it the easy way:
Bolt on the slave to the bellhousing LOOSELY. (Bleed screw down, per factory)
Screw on the fluid line, and tighten it snugly.
Remove the slave from the bellhousing, and turn it upside down, so the bleed screw is the HIGHEST POINT.
Now open the bleed screw, and let it gravity bleed for 30 seconds.
Close the bleed screw, and remount the slave.
95% of the time, after this, I'm done.
The other 5%, I pump the pedal by hand a hundred times, 'til it returns

[01CT540i]

I'm glad to have benefited from your experience Chris! I've seen your advice for folks with misfires and have taken that too! My 540 was suffering from intermittent misfires the last few days since getting back on the road and this morning it got bad so I had it towed to my local independent BMW specialist (Munich Motorsports). This part of the story is probably best left for a different thread. Just a warning - now that you have shown me you're an expert I may be back to bother you much more in the future! Thanks again!!!

[bmwdirtracer]

I'm glad to have helped. If it were a bother, I wouldn't be here.....