Aluminum flex disc (guibo)

matreyia

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Apr 19, 2017
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Cliffnotes of my experience -- keep in mind I absolutely baby this car:
  • tore down the car at 103,000 miles to install a single turbo and upgraded clutch.
  • purchased a pre-owned aluminum guibo seen in my last post with low miles to install while the transmission was out.
  • the part looks great when it arrived and the flywheel, clutch, transmission and guibo all went back in without trouble.
  • immediately began noticing NVH at low speeds in 1st and 2nd gear that would quickly go away as speed/gears increased, which I attributed to the MFactory SMFW, as most people have this complaint.
  • daily drove the car for 10,000 miles with no issues, no funny noises or vibrations aside from what I'd understood to be normal SMFW behavior. These 10,000 miles included 0 launches, 0 1st or 2nd gear pulls, only 10-15 WOT pulls through 3rd and 4th gear at 17psi because I quickly realized I needed more fuel to push it further.
  • pulled the car in the garage yesterday to start installing fueling mods, and as I was looking over everything and doing a bolt check on the subframe and suspension components I'd removed/resinstalled for the single turbo conversion, I discovered the busted guibo.
I also live in the south with pretty decent roads and have my daily route memorized to avoid all potholes.

I can really only chalk this up to a lousy part or design, especially given how this part has a somewhat mysterious past over the years across different models. My 103,000 mile rubber guibo still looks brand new, so I'll likely never mess around with going aluminum again.


Ahh.... you bought a used unit. That's different. I would be very surprised if you got it new and it went kablooey from never launching. There is not way to tell what the unit has been through and no way to test it so who knows. You are the first person I ever seen to have that kind of damage or any at all on an aluminum unit.
 

chadillac2000

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Oct 26, 2017
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Ahh.... you bought a used unit. That's different. I would be very surprised if you got it new and it went kablooey from never launching. There is not way to tell what the unit has been through and no way to test it so who knows. You are the first person I ever seen to have that kind of damage or any at all on an aluminum unit.

Perhaps. It was in fine condition when I installed it with no stress cracks in the aluminum or rubber bushings whatsoever. Also, there's plenty of reported failures from these online, I'm far from the first. A few 1M guys with this guibo installed have posted similar destruction shots.
 

matreyia

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Apr 19, 2017
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Perhaps. It was in fine condition when I installed it with no stress cracks in the aluminum or rubber bushings whatsoever. Also, there's plenty of reported failures from these online, I'm far from the first. A few 1M guys with this guibo installed have posted similar destruction shots.

And do you know if all those guys had new units or used ones? Also, did you use a microscope or magnification to inspect the unit. It only takes one single microscopic fracture to start the whole down hill slide. I had a microcrack on an intake manifold...and you would never believe it from visual inspection...could not see a thing wrong, until you tested it for leaks with smoke.
 

chadillac2000

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Oct 26, 2017
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And do you know if all those guys had new units or used ones? Also, did you use a microscope or magnification to inspect the unit. It only takes one single microscopic fracture to start the whole down hill slide. I had a microcrack on an intake manifold...and you would never believe it from visual inspection...could not see a thing wrong, until you tested it for leaks with smoke.

The 1M models I was referencing as also having failures came with the aluminum model straight from the factory, so not sure the used versus new argument applies. Technically every single part on all of our cars are used. With the aluminum guibo in particular, it seems they can come apart at any time under any circumstance. To answer your other question, of course I didn't get out a microscope to inspect if there were micro cracks in the pre-owned metal guibo I bought, but I did look it over closely and it was good to go. Maybe the previous owner had really abused it, right up to the point where it was about to break but didn't, and then sold it to me to break soon after, but that seems like a long shot.

Based on the mysterious history of the aluminum guibo in general, the apparent recalls, and picking and choosing of which models to put this in directly from BMW, I think it's safe to say it's probably better just to stick with the rubber version -- unless you're already running the aluminum version and aren't having issues. I just wouldn't go out of my way like I did to track down an aluminum version on the basis that it will be stronger and further remove drivetrain slop.

To update the situation I originally posted on, after finishing up installing a Fuel-It stage 3 LPFP, Phoenix Racing PI IM, and upgraded fuel lines, I swapped back on my old 103,000 mile old rubber guibo and finally got to drive the car a bit. I did note some ever so slight stress cracks starting to form in the rubber near the bushings on this one before I bolted it back in. To my pleasant surprise, probably 99% of the NVH was experiencing and blaming on the SMFW immediately remedied themselves after reinstalling the rubber guibo. A night and day difference in vibration, downshifts are now easier to rev match cleanly, and I no longer experience the the "rocking" sensation I was getting when quickly letting off the throttle at most speeds. I'll probably grab a brand new rubber version and install it during my next oil change just to be safe and avoid future problems and vibrations.
 

matreyia

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Apr 19, 2017
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The 1M models I was referencing as also having failures came with the aluminum model straight from the factory, so not sure the used versus new argument applies. Technically every single part on all of our cars are used. With the aluminum guibo in particular, it seems they can come apart at any time under any circumstance. To answer your other question, of course I didn't get out a microscope to inspect if there were micro cracks in the pre-owned metal guibo I bought, but I did look it over closely and it was good to go. Maybe the previous owner had really abused it, right up to the point where it was about to break but didn't, and then sold it to me to break soon after, but that seems like a long shot.

Based on the mysterious history of the aluminum guibo in general, the apparent recalls, and picking and choosing of which models to put this in directly from BMW, I think it's safe to say it's probably better just to stick with the rubber version -- unless you're already running the aluminum version and aren't having issues. I just wouldn't go out of my way like I did to track down an aluminum version on the basis that it will be stronger and further remove drivetrain slop.

To update the situation I originally posted on, after finishing up installing a Fuel-It stage 3 LPFP, Phoenix Racing PI IM, and upgraded fuel lines, I swapped back on my old 103,000 mile old rubber guibo and finally got to drive the car a bit. I did note some ever so slight stress cracks starting to form in the rubber near the bushings on this one before I bolted it back in. To my pleasant surprise, probably 99% of the NVH was experiencing and blaming on the SMFW immediately remedied themselves after reinstalling the rubber guibo. A night and day difference in vibration, downshifts are now easier to rev match cleanly, and I no longer experience the the "rocking" sensation I was getting when quickly letting off the throttle at most speeds. I'll probably grab a brand new rubber version and install it during my next oil change just to be safe and avoid future problems and vibrations.


Hmmmm you get the rocking sensation too? Perhaps update when you get a new rubber guibo... I would definitely go rubber if that helped my rocking sensation during shifts under high throttle.
 

ShocknAwe

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Jan 24, 2018
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I've heard of nothing but failures with these aluminium guibos. I'm experiencing some rocking in my driveline on my 100k rubber unit. Attributr it to driveline backlash. Going to replace it with a new one when I install my lsd and clutch. Won't help much to DX the issue, but I bet it will be gone arter.
 
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chadillac2000

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Oct 26, 2017
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Allow me to eat crow here. While I'm not going back with an aluminum guibo, the reason mine was destroyed was probably of my own doing. Read below from my build thread:

Back when I was installing this latest round of fueling mods, I touched on the fact that I had found my aluminum guibo completely destroyed.

ZVPnOcB.jpg


I had attributed this failure to all the clunking and drivetrain vibration I'd been experiencing in 1st and 2nd gears. While the car was up on stands, I swapped back in the OEM rubber guibo the car came with back in 2008 and torqued everything back in. Keep in mind, I did not drop the mid-pipe portion of the exhaust, nor did I drop the heat shielding above that shields the driveshaft from the elements. When I got the car back on the road to test out the port injection and second Walbro 450, it seemed that most of the problem had been resolved. I could still feel the vibration I was experiencing with the aluminum guibo, but it had become much more manageable.

Over the next few weeks, however, things had gotten worse and most of the vibration had returned in 1st and 2nd gear. In fact, in 1st gear under anything but the lightest of throttle, it sounded like the driveshaft was making contact with metal. I limped the car to my garage, and got the car back on stands again. To my surprise, the guibo was still intact and didn't look ripped in the slightest.

lPtsEfU.jpg


This meant the center support bearing was the next possible failure spot, but getting a clear view of that portion of the driveshaft meant dropping the mid-pipe and heat shielding. At that point, it was obvious the center support bearing was destroyed and the culprit of the harshness I'd been experiencing.

The other obvious issue was that back when I'd dropped the driveshaft to upgrade my clutch/flywheel earlier in the year, I had not paid close enough attention to the orientation and installed it upside down. This was putting the angle of the driveshaft slightly off kilter, and therefore trashing the center support bearing itself, as well as the guibo.

VzavGdG.jpg


I was disappointed in my dumb mistake, but it's not the first nor the last I'll make while wrenching, and now I know for sure what was causing the issue. I used FCPEuro to pick up a brand new OEM BMW guibo and center support bearing. The lifetime warranty on some of these wear and tear items is valuable in my eyes.

I started at the guibo end of the driveshaft and disconnected those 6 bolts. Most DIYs I reviewed recommended pulling the driveshaft at the differential end, but I did not have the 50mm open end wrench in order to remove the oversized nut. This meant leaving the driveshaft attached at the differential, disconnecting the two bolts securing the center support bearing, and pulling back the rubber boot to expose the splines of the driveshaft.

At this point, you'll want to mark the two ends of the driveshaft so they can be reassembled in the exact same way they were removed. The driveshaft is balanced as a single unit and has weights in certain areas for vibration free driving. From there, a 3 jaw puller made light work of getting the center bearing removed from the driveshaft.

9ARHNNn.jpg


Old parts compared to the new ones.

s8MUkDC.jpg


New guibo on the left, old cracked guibo on the right.

AwfrhGY.jpg


To install the new center support bearing, make sure the old one is installed in the same orientation as the old one. I marked mine just to be sure. I used a pipe that was slightly larger than the driveshaft spline and a rubber mallet to push the bearing up the shaft and into place. A press was not needed.

This time around, I made sure I had the center support bearing properly rotated before bolting it down. This made a huge difference in how the driveshaft sits, and tucks much better up in the tunnel.

s81avqn.jpg


Final look at both ends after bolting everything back down properly. When reinstalling the guibo, make sure the arrows on the outer ring are pointing towards a flange. That will ensure everything is oriented properly.

g36vBrv.jpg


1H7NFZZ.jpg


Hopefully this can help someone else avoid this very avoidable problem. At least both of the guibo and center support bearing are considered wear and tear items, so its nice to know there's fresh rubber in there.