Loud thud when going into reverse SMG, strange clutch egements

[Nico]

I had a similar loud clunking issue when downshifting at higher RPM and what felt like weird shuttering and chatter at low speed. It turned out the front poly diff bushing extruded itself onto the diff and out of the housing. I just replaced it with the upgraded design from revshift. The car no longer has these issues and drives very solid.

I would suggest two things:
1. Run the smg bleed and adaptation procedures again. I ran mine like 5 times after my relocation lol.
2. Check the front diff bolts and all diff bushings.

Good luck and hopefully this helps!

Thanks

[BMW_QAS]

Before I swapped out to manual my car had semi-similar issues. Took a long time to go into reverse, gear change indicator would blink and the car would not go into gear, only gears selectable were odd gears 1,3,5. As it turns out my car had multiple problems.

The transmission mount crossbar was cracked in two places and the “ears” of the transmission were broken off. Nothing was physically supporting the transmission. Car had aluminum mounts on the engine and trans.

Inside the transmission bellhousing the plastic shift pivot point was broken completely. The shift arm was free floating. The throw out bearing looked original, and had copiously large amounts of sludge and yuck all over it. The clutch disc was worn almost to the rivets.

What I’m trying to say is: You may have multiple issues. Don’t rule anything out until you or a mechanic you trust looks at the system as a whole.

Good luck,

-Steve

[BMW_QAS]

Here is the cross brace. The cracks could not be seen by just looking under the car. The crossbar fell apart when the load on the transmission was removed.

[eacmen]

Here is the cross brace. The cracks could not be seen by just looking under the car. The crossbar fell apart when the load on the transmission was removed.

You think the solid mounts led to this failure?

[Nico]

Before I swapped out to manual my car had semi-similar issues. Took a long time to go into reverse, gear change indicator would blink and the car would not go into gear, only gears selectable were odd gears 1,3,5. As it turns out my car had multiple problems.

The transmission mount crossbar was cracked in two places and the “ears” of the transmission were broken off. Nothing was physically supporting the transmission. Car had aluminum mounts on the engine and trans.

Inside the transmission bellhousing the plastic shift pivot point was broken completely. The shift arm was free floating. The throw out bearing looked original, and had copiously large amounts of sludge and yuck all over it. The clutch disc was worn almost to the rivets.

What I’m trying to say is: You may have multiple issues. Don’t rule anything out until you or a mechanic you trust looks at the system as a whole.

Good luck,

-Steve

Could be, my car has never had an issue engaging any gear after the motor replacement though.

Took it for a drive yesterday, this time when I started it up, waited for the RPMs to drop after being cold and no slamming in reverse. Weird.

[BMW_QAS]

You think the solid mounts led to this failure?

100%, Yes. I think they probably began as small stress fractures in the aluminum. From there it was only a matter of time and repeated stress. Those mounts would work better with a steel or titanium crossmember, but not weak cast aluminum.