help! strange noise after changing t-box bushes

Hi guys,


My t-box bushed were knacked so i took the opportunity to up grade the to a set of HD bolt thru ones.

Other that the fact that the old ones were a pig to get out the job went fine.
But ive now got a strange rumble/vibration in gears 2,3 and 4 at around 2.5 to 3k rpm.
its only there for a couple of seconds and then its gone.

im not sure what could be causing it as im pretty new to 4wd and working on my own car in general!

it may be nothing, but im concerned as it wasnt there before.

any help greatly appreciated.
Joe

Might just be that the new mounts are stiffer: the originals are all wiggly to prevent the noise and vibration from reaching the cabin.