Thud/Clunk Noise

[jdw1]

I have a clunk or thud type noise coming from under the car sounds like its where the rear diff is maybe. It happens when I'm down shifting and finding the lower gear initially when putting it into the lower gear, that's the thud. The clunk is if I let out the clutch quickly it's more of a clunk. Normal driving there's no noise, only when the stick first hits a lower gear or a quick clutch release. Any ideas? Thanks

 

[zinger002]

check your bolts on the mounts you have installed.

 

[jdw1]

Got up under it over the w/e and everything seemed tight. Wiggled the diff pretty hard by hand and inspected the bolts and no movement at all. Didn't have a wrench on them but initial inspection was seemingly a pass. I'm not even sure what the noise could be, things are tight in there and from torque seemingly it could bump but this noise come when I hit a lower gear so weird to me.