::.. Shifter vibration... different

[Qube]

First off, I've searched around here and noted several fixes, but I want to get a 'fifth' opinion.

Symptoms:
- accelerate in 1st, shifter noticeably vibrates left and right
--- put hand on shifter and feels like something is slapping against it in 1st
- no acceleration = no vibration (not noticable anyway)
- accelerate in 3rd above 2000 rpm or so and vibration but way less than in 1st
- no problems noticed in 2/4/5/R
- SEEM to hear the 'vibration' under the car when moving
- clutch in and rev in 1st or 3rd, no vibration

Why I think this is different is that it feels like something is slapping against the shifter somewhere. While probably not possible, imagine the driveshaft was warped and continually slapped against the shifter as it rotated... increasing in frequency as you accelerate.

With my limited knowledge (but plentiful in 1/8 and 1/10 scale nitro R/C), it feels just like the scenario I put above... if that helps you visualize how it may feel. In 1st, it's almost always there. In 3rd... maybe 80% chance it does.

Now then... open floor for comments...

[Martin in Bellevue]

Have a look at the driveshaft center support bearing, the guibo, & transmission mounts for the cause of the vibrations.

[Qube]

Polling for any further ideas...

[Dave M]

Polling for any further ideas...

Martin has provided the most likely source(s).

The easiest things to check are the tranny mounts.

Then, unless something has 'stuck' itself to the front of the driveshaft or flex disc (check its condition) and is slapping against the shifter rod, you'll have to remove the exhaust, heat shield and check the condition of the center bearing. Any vibration caused by a failing bearing will inevitably find its way through the tranny and shift linkage, and eventually your seat :)

dave M

[Derek A.]

There are no further ideas. I chuck of Guibo is slapping the shifter linkage. Gut it fixed ASAP before you rip somthing up.

[Kobe Diesel]

Check underneath the car and see if the shift linkage rubs against the drive-shaft in any of the gears. If your driveshaft is equipped with a vibration damper (mine shrouds the guibo), sometimes the linkage and this part come in contact. It's not likely, but worth the check.

[Qube]

Got it. I'm bringing it in tomorrow so I can lift it up. I was hoping there would be something to clue in being only 1st and 3rd gear positions... some way the forks are positioned perhaps. Tomorrow :) Of course, I said that about the fan belt and was one day too late. *touch wood*

I had no idea what the guibo was so for those wondering:
http://pages.sbcglobal.net/gorf/bmwtips/maintguibo.html

http://i17.ebayimg.com/02/i/03/2a/cc/f5_1_b.JPG

and of course... http://www.bimmer.info/forum/search.php?searchid=169913

Especially http://www.bimmer.info/forum/showthread.php?t=13149&highlight=guibo