Subframe and Differential bushing ???
 

Just installed whiteline subframe insert bushings and Differential mount cradle insert bushings. Followed instructions close with no problems with bolt reinsert and proper torque spec. Now seems to have a wine through first gear after that nothing. Anyone else done the subframe and differential inserts?

Of course installing more rigid/less compliant bushings can increase NVH by not dampening vibrations/noise, that's given. Though i'd rather expect to hear some whine from gearbox mount/bushing change, not diff's, but it's after shaft next in transmission, possible. (also my guess is that whine is also in other gears, just that drowns in road/tire noise in faster speeds/lesser rpms, so you don't hear it).

Yes the whine is only present in first gear

To me whine was also in 2nd, and though rarely, sometimes i caught glimpses of that SC sound-alike quiet gear whine in 3rd too. Hence my idea that it's still there .. just that is drown among increasing other noises from tires/road/wind.

Thanks all just worried I did something wrong during installation. Going to be replacing differential oil anyway have about 60,000 miles on it now. Also thinking about putting some sound deading material under seats to cut some of the road noise. Anyone do the steering rack bushing. Anything I should expect from doing this? Noise, feel, vibration, anything ???