Body jump when releasing driving brake

I am noticing an issue when releasing the brake which cause the body, from what I feel, to reposition a small amount.
SYMPTOMS
Fully stopped for one reason or another, as I release the brake, I don't hear so much but more feel in my butt sitting in the seat, a body jump or maybe mechanical movement causing enough vibration to be sensed.

WHAT I'VE DONE
Practically nothing but think about what it might be. Maybe it could be the bolts that hold the body on the chassis or some kind of transmission or engine mount?

Body mount bolts...but unless someone dis a body lift or had the nody off for some reason highly unusual for them to loosen up...especially all of them. Have you also checked the seat bolts?

seat bolts were my thought also.

'Seat of the pants' sensations are hard to diagnose. I agree that body mounts are unlikely to loosen up on their own so unless somebody monkey'd with them, they are an unlikely suspect. The bolts holding the seats to the floor are in kinda the same boat. Unless somebody monkey'd with them, they are unlikely suspects too. I wouldn't totally rule out either & both are easy to check so go for it.

More likely would be the tranny mounts. Several members have posted that theirs have worked loose & in some cases were actually missing bolts.

Also look for the thread where Ldub discussed his waggly rear end. He had found that some of the holes in the frame for the rear suspension had egged out allowing for some squirrely movements.

http://www.vehicross.info/forums/sho...ghlight=waggly

I'm bettin' it's the trans mount bolts for the crossmember. My Proton was making some odd movements and noises when I first got 'er and I found she was missing the rear trans mount bolts to crossmember. Put in two shiny new grade fives and nylon locknuts and problem solved. Still haven't figured out why those just decide to fall out but I'm not the first to have had that issue...:_confused

Scott, probably has to do with vibration and the twisting torque that the mount experiences.