clunk when shifting

[babycarlos]

hey guys for quite a while now i've been feeling this clunk when i shift fast. i heard that it could be my diff mount bushings that are going bad. i know that my trans mount is bad and i will be getting one, but aside from that what else could it be. i've also notice that with the car on and in neutral, when i let go of the clutch quickly i get a slight clunk. but if i do the same thing with the car off i get nothing. could this be related to the fast shifting clunk, could it be worn input shaft splines, etc.

[impreza_GC8]

The clunk is normal. It used to happen to me years ago nearly every time I shifted but I got used to driving Subarus and it doesn't happen anymore. I believe Turn In Concepts sells a "clunk-killer" bushing kit if you really want to be able to shift hard with no flex. I have yet to install this because I haven't done any bushing work with either of my cars (yet).
The clunk that comes from releasing your pedal quickly in neutral is actually the pedal slamming when you release it.

[anothernord]

+1 for TiC's "klunk killer". The kit includes both rear differential bushings as well as rear subframe outrigger bushings. I currently have only the outrigger bushings installed, and it has nearly eliminated all of my clunk, now its sort of a "click".