Diff noise after seal change

hey all,
as you may know I have had a few probs with my rear diff.
I got the garage to replace the pinion oil seal and after this the diff started to make a low pitched growl/wob/bearing noise when slowing down. so took it back and they put new seal and spacer in..still same noise and then a new high pitched whir in overrun! great!

they told me it was my IRd making noise so I took it to another Freelander garage who said ird was fine and they fitted new oil seal as the previous garages attemp was still leaking!

concerned with noise I took prop off for two weeks (had a new VCU and prop bearings fitted a few weeks ago and 4new tyres all same size fitted) I saved some money and paid for the diff to be overhauled as the pinion had lateral movement. Diff overhauled with all new bearings-took it outfor a drive and noises were still there!! and slack came back in pinion!
back to garage who retightened pinion nut and slack all now gone, no leaks and that cured the high pitch whine on overun.....but I'm still left with the low wobwob bearing type noise from diff when slowing down!
when diff was overhauled the crown and pinion looked ok I was told!


so...help! shall I live with this noise in diff, anyone else have the same noise at all?

its probably been damaged by been run with brg incorrectly set after first seal fitted ,you cant allways easily see damage a bit like running flat tyre and then inflating it and finding it looks allright but doesnt drive right

damage to crown/pinion?
just paid a song to get it overhauled...maybe run this one to destruction then get a new one? already put some Lucas diff additive in to help the diff out a bit..should have bit the bullet and got a new one for the sake if the extra £250 compared to overhaul..SHISEN!!

you dont find too many mechanics than undestand how things work ,any mechanic worth his salt should know that taper brgs would need to have preload set even if they had never worked on that diff before its an engineering principle

I've been assured that the new taper bearings that were installed were torqued up ok...and the tightened a bit more to reduce noise..I'm guessing as bearings are new the noise must be emanating from the crown and pinion..which may also be causing the everso slight vibration felt at 55mph. any sound must be generated via energy released from two metal surfaces not interacting efficiently which means after some time I'm gonna start chipping teeth I guess..why can't I find a decent garage in Norfolk who know these diffs inside out! grrrrrrr

if you get stuck i can have a look,i do diffs etc for a living unfortuneatly im in lincs but carriage is cheap

pm sent thanks chief..I'm in kings Lynn. been offered a new diff with 6months warranty - not sure if I should get this or just replace the crown and pinion in my diff as I've already spent £500 getting it overhauled!!