megamacx

Hi Everyone,

I have had an issue for over a year when engaging/disengaging the clutch of my 5 series (E60 LCI) 535xi manual transmission.

NOTE: Both engine mounts, wishbones and lower control arms were replaced about 3 weeks ago by brand new OEM parts. I also changed the transmission oil and transfer case oil about 2 months ago.

I want to get to the bottom of it, but I need some help.

Basically there's a clunking noise that is mostly noticeable when I start driving (by engaging the clutch on 1st gear, and it is also noticeable on 2nd and if I pay attention on 3rd gear).

When I can make the noise be the loudest (clunking) is when I test the car doing downhil on 1st gear, driving at about 10 mph, and then disengaging the clutch, and re-engaging it several times.

I put a camera on the bottom of the car, and recorded a couple of videos where the transmission and mostly the transfer case can be seen not only shaking when I disengage, but also making the noise.

If I am on 1st gear and push and release the throttle quickly, the car doesn't feel tight and firm but somewhat loose.

From what I have read and seen, to me this seems to be the transfer case mainly.

My mechanic examined the car in a lift, and he disagrees. He said (without taking the transmission or the transfer case out) that there's a grinding noise coming from the transfer case, but the clunking noise is actually coming from somewhere inside the transmission.

Here are the links:

(Video 1)
(Video 2)

On video 1, after minute 1:00, I stop the engine and start disengaging/engaging the clutch at a low speed in a downhill to reproduce the clunking. On the right side of the screen you will see the transfer case, and behind that (not too visible) the transmission.

On video 2, the transmission is visible on the left, and the transfer case on the right at the bottom.

I asked him if the transmission mount could be bad, and he said it was not to the point where it needed replacement.

What do you guys think? Is this transfer case or transmission? My mechanic said not to do anything, just make sure that when switching gears I press the clutch completely to the floor (which is what I've always done).

I want to check how much would it take to get this problem fixed (through either replacement or repair) and what makes more sense.

Thoughts?

turboawd

its a possibility your driveshaft u-joints may be getting dry and stiff, and amplifying and drivetrain slack or vibes.or maybe slack in the transfercase chain.

megamacx

Where do you think is the noise coming from?

DBU

Transfer case...

audiophool

The transfer case sure is moving around a lot...

megamacx

Now, if is the transfer case, do you guys think this can be repaired/rebuilt? As far as the transfer case moving, is this normal, or should I also be thinking about a busted transmission mount?

As far as I understand, the transfer case is the ATC-300

http://www.ecs.steyr.com/typo3temp/pics/b19fc59d99.jpg
http://static.bmwfans.info/images/epc/MTQ4OTk3X3A=.png

audiophool

From the first clip it appears the TC is moving separately from the transmission. Unless that's an optical illusion in the video, the TC, which is bolted to the back of the transmission, is moving separately. But I'm sure your mech would have seen that.

megamacx

It shakes when I go downhill on 1st gear and I disengage the clutch. So every time on the video that is shaking separately, is because II am disengaging the clutch going downhill. It might look like the Transfer Case is moving separately from the Transmission, however, I guess since the transfer case is closer to the camera, that's why it looks like it is shaking by itself.

What are the components I need to inspect to prevent the Transfer case and transmission to shake that much? Since I replaced the engine mounts, what else could be causing the transfer case and tranmission to shake like that (it seems as if the transmission wasn't just hanging off the engine and not supported with anything).

megamacx

Doing more research on this issue.. Could this be the related to Front/Read differentials? The car has 66k miles on it and I haven't replaced the diff oil yet.

Could it also be something going on in the Guibo/Center Support Bearing?

v_therussian

I had a similar issue, minus the grinding, and was able to identify a faulty transfer case mount. Part number is 22316773125. Look into it. I just swapped mine out and the issue seems to be resolved.

If this doesn't help, find someone with a boroscope to inspect the TC's internals. Could be the chain.