Thumping Noise Under Car

kys911t

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I have an automatic and with slight acceleration I noticed that there is a slight thumping noise under the car. Some one told me my guido is bad. Any other thoughts.
 
Thumping under car--cause may be

the center bearing--when it's torn/failed/about to fail--from torque when power is being applied it will thump.
 
+1 and while you're replacing the center support bearing go ahead and replace the guibo/flex disc - they're both only about $50 each and easy to do. If doing this yourself you'll need a bearing puller (I modded a cheapie from Harbor Freight) and a suitable diameter pipe to hit the new one on. The guibo comes with a compression strap on it - don't release it until its been installed.


the center bearing--when it's torn/failed/about to fail--from torque when power is being applied it will thump.
 
buy Febi on the center bearing if you can and avoid BMW dealer trash [80 bucks made in Taiwan]
 
Well maybe...

maybe it's the center bearling and maybe it's not, but when my coupe with AT made that noise on corners, it was the rubber mount between the trans and crossmember that was bad. A much simpler, less expensive repair for one who always does his own work.

Good time to check the motor mounts too, particularly the left side.

Now for the HOW which is commonly left out of responses. (shame on ya)

Remove the dshaft for giubo or center bearing inspection/replacement requires dropping the exhaust IIRC. Maybe you can do it without. The nuts between the downpipes and headers will be really rusty and need your favorite penetraing oil, plus 18" extensions for the socket. Don't bust your knuckles when they let go. If you bust a stud your penetrating oil didn't work, and the header has to come out (6x12mm nuts) supposed to buy new nuts and gasket to replace.

The giubo is secured with 3x19 mm nuts on AT's, and 6x19 mm on MT models. They will also be tight, use a 19mm socket one side and 19mm box wrench on the other. Center bearing, 2x13mm nuts to body, dshaft to diff is 4x13mm with special bolts. When/if you separate the two piece dshaft, you WILL have ALREADY marked it to put back together in the same rotational orientation. You can remove the center bearing from the dshaft with creativity, elbow grease, appropriate force and strong language, without a bearing puller.

If I've got something wrong, someone should (and surely will!) correct me.
 
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Center bearing feels really sloppy so Im going to change both as long as I have the car in the air.
 
Any Suggestions on where to buy the Center Mount & Bearing and Guido. Febi has been suggested.
 
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