Originally Posted by renns (Post 5868343)

I can't say for certain, as I don't have an S4 box open at the moment. I can say that the three shift rods that extend into the box are in the same position in both the SA and S5 trannies, and likely identical on other models as well. The actuating rod from the shifter is in a different position between those two boxes. The shift fingers are definitely in a different orientation between SA and S5 to accomodate the different actuating rod position. Below is a pic of the S5 shift finger positions for comparison if you have an S4 box open.

https://www.rx7club.com/attachment.p...d=185159&stc=1

The dynamic damper is a small flywheel-type device, rubber isolated from the hub which is locked to the output shaft. It spins with the output shaft inside the extension housing. It definitely interferes with the SA housing, but I can't speak to the FB housing. The damper is easy enough to remove if needed. That huge nut tightens on to the body of the damper, pushing two tapered sleeves between the damper and shaft to lock it in place. A couple whacks with a hammer and punch, and the large nut spins off easily. Then remove the retaining ring below the damper, and give the damper a tap to slide it off those tapered sleeves. All components slide up off the end of the output shaft, leaving you with a box that appears ready to accept an SA or FB extension housing.

https://www.rx7club.com/attachment.p...d=185158&stc=1

Originally Posted by SpideyFan6010 (Post 8466922)

What exactly does a Dynamic Damper do? And do I REALLY need it.

Originally Posted by renns (Post 8468022)

Wow, up from the past!

Perhaps the purpose is to dampen some vibration problems in the stock S5 install. Given the other transmissions don't have such a dampener, one might consider it optional. Also, if the S5 transmission is to be mated to other than stock S5 drivetrain components, then the dampener may no longer be of much use anyways.