Vibration after transmission swap

[kanada]

Background 1987/11 325is - vin says it is automatic, but it had getrag 260 when I bought the car couple years back. Replaced clutch pilot bearing, etc couple years ago and replaced seals on the transmission. The selector shaft seal leaked even after 3rd change. Synchros on the transmission where bad on 1st and 2nd gear.

Since I had 2.7 engine and transmission, I decided to swap out the getrag. Gave the engine to anther e30 owner ;)
It is a major PITA to change the transmission without pulling the engine with car on jack stands.

Today drove the 325 to work - Major vibration above 2800 RPM no matter if clutch is in out. Car speed does not matter. What can be wrong here? :(

[Sagaris]

I had a similar bad vibration which turned out to be broken transmission mounts.

[MitchD1283]

Make sure you have the same size nuts on all of the bolts for the driveshaft. Someone played a lil joke ok me and double nutted one bolt on the driveshaft. It caused a vibration throughout the whole car. It was more speed dependent though.

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[jlevie]

That would make me think of binding u-joints in the drive shaft.

[kanada]

The vibration is engine speed related not wheel speed related.

Doing 60mph in 5th gear no vibration - engine rpms below 3k.

Car stopped rev up engine past 3k - vibration clutch ir out does not matter.

I am puzzled

if vibrates with clutch pedal released - transmission input shaft/bearings, but when press clutch pedal (transmission input not turning) it still vibrates.... can this be purely engine problem?

[kanada]

One more thing - I changed the transmission mounts to these

http://www.harrisonmotorsports.com/akg-group-n-transmission-mounts-e30-36-46-z3.html

local bmw dealer wanted $37 for a mount and did not have them in stock, so I just stopped by harrisons and grabbed these.

can stiffer mounts cause this much vibration in the seat?

[kanada]

For anybody else vibration was due to the urethane transmission mounts. Switched to new oem rubber ones and vibration is gone.

[ANDRÜ]

Interesting. Thanks for the update