driveline noise when reversing direction

[maint]

I had my 850i on a four post hoist yesterday and we checked out a noise that occurs when shifting either way between fwd and rev. I tried to upload a video of the sound but couldn't . It sounds as if a fan blade hit on a bit of metal very briefly, one or two blades; almost a metallic rattle. It's hard to pinpoint as the noise seems to reverberate from all of the rear driveshaft. If I had to guess (which I am doing) I would say it is from the front end of the rear driveshaft at what looks like a carrier bearing. Does this seem familiar to anyone? How do these usually go ? Access is very limited, to investigate further I will need to drop the exhaust. Turning the driveshaft by hand I can't feel anything and no slack

[JDP530]

I think Steffen has mentioned that a worn diff carrier mount or final drive bracket (33171136332 on early models) on front of diff will cause a knocking sound when going in to reverse. There is a rubber bushing in the bracket that can wear out and allow some diff movement. Item 15: It will be a different piece on late model cars.

https://www.realoem.com/bmw/enUS/sho...diagId=33_0394

[maint]

There is no clunk or knock but there is a small bit of diff movement when shifting direction. Worth checking it out, maybe it is causing something to bind. I hope it's not as ,on RealOEM, the bracket is 'ended' and the one that superceded it is 'nonexchangeable retrospectively' which I assume won't fit

[JDP530]

There is no clunk or knock but there is a small bit of diff movement when shifting direction. Worth checking it out, maybe it is causing something to bind. I hope it's not as ,on RealOEM, the bracket is 'ended' and the one that superceded it is 'nonexchangeable retrospectively' which I assume won't fit

I rebuilt the complete rear suspension in my car several months ago and the bracket for the early model was available but it was around $200. There is one rubber/metal bushing in the bracket that was not available as a replacement but its possible another bushing from another part might fit but I didn't try to identify one that would work. If I am not mistaken the bushing measured 60 mm overall width, with a 50 mm width for metal jacket, 49.25 mm OD, and 14+ mm ID for 14 mm bolt. I never took the time to compare size with all the other bushings that came out of rear susp.
IMG_20190414_191837362.jpg

Here is part listing on scorebmwparts.com site: https://scorebmwparts.com/parts/1991...iagram=1919445

[mandd]

If it is a distinct "ping" type noise then check the rear C.V. joint (26 11 1 229 098) on the propeller shaft. If the noise is from this then remove, disassemble, clean and repack with C.V. grease. The splines for the driveshaft at the hanger bearing can also cause this noise, if it is from there then clean the splines replace the hanger bearing and fill the spline valley with a high pressure type grease, then refit.

Mark.

[maint]

Got it back in the air and removed the two bracket bolts on the diff. The bushing appears good and the movement seems to be normal. I'll take a closer look at the rear cv joint and soak the exhaust bolts for luck.

[Amo3686]

The CV joint tends to have a clicking noise or pinging as you drive, especially at lower speeds. Then it can start causing a vibration along the prop shaft as it worsens and usually goes away above 40-50 mph. If it is the CV joint, it will be easy to get a replacement since the same CV joint is used on various BMW models up as far as the E39 5 series if I remember correctly. The trouble is the CV joint tends to dry out and the bearings get corroded. If the car has not moved for a long time the CV joint can dry up.

When I purchased my 840 it had only done about 300 miles in 3 years due to previous owner not driving it. A month after I purchased it and using it as a daily driver, the CV joint started clicking/pinging and after a few days it was causing vibration. Not sure if you are getting these symptoms.

[maint]

Hasn't been driven much in the last couple of years and not at all since Feb. Didn't make this noise before it went in the shop for suspension and upper oil pan and it is not a loud noise. Can't feel anything wrong turning the shaft with wheels held or not. I'm soaking the exhaust studs and will pull the exhaust next to better eyeball the driveline. It is not serious yet but I would rather know what's happening before I break down someplace in the middle of nowhere

[rjjablo]

I rebuilt the complete rear suspension in my car several months ago and the bracket for the early model was available but it was around $200. There is one rubber/metal bushing in the bracket that was not available as a replacement but its possible another bushing from another part might fit but I didn't try to identify one that would work. If I am not mistaken the bushing measured 60 mm overall width, with a 50 mm width for metal jacket, 49.25 mm OD, and 14+ mm ID for 14 mm bolt.

Has anybody identified a replacement bushing from stock from other than BMW?

Is there anything special about this bushing?

[JDP530]

Wolf Ganssauge mentioned on Facebook that he is going to find or make a replacement. So maybe we'll see one from www.wokke.de.

[rjjablo]

Wolf Ganssauge mentioned on Facebook that he is going to find or make a replacement. So maybe we'll see one from www.wokke.de.

Thanks

[Ericks2002]

Any info on a new bushing? Putting my LSD in this weekend and noticed the bushing is looking rough. Replacing the rear two but the front is still NLA.

[rjjablo]

Wolf said he would have a prototype last week. E-Mail him

[Ericks2002]

That’s great. I’ll shoot him an email.