Loud Violent Clunk When Shifting FMX Into Gear. Any Transmission Experts?

[Hemikiller]

TBH, that is a lot of movement in the diff. Here's a video of the 2.75 rear I just removed from a car. I consider this excessive, and yours is much worse.

 

[Don C]

TBH, that is a lot of movement in the diff. Here's a video of the 2.75 rear I just removed from a car. I consider this excessive, and yours is much worse.

It doesn't take much wear on the differential bearings to dramatically increase the backlash. Harsh transmission engagement with a small amount of backlash will make a noticeable bang.

 

[Precision Transmission]

Did you ever do that Control Pressure check?