'07 Grand Cherokee mystery clunking/grinding from front end

[limey.ca]

I have an '07 Grand Cherokee Diesel (high kms) that has a clunking/grinding noise from the front end. So far this has defied 3 dealers and 1 independent shop. It's fine when cold but after only a few km's the noise appears first as a grinding then as a vibration that can be noticed ( more so when on the overrun), it becomes really apparent when at slow speeds whilst turning. To date it has had both front CV driveshafts replaced, a corroded switch has been cleaned (that cured the service 4WD message!lol) and a new hub assembly. I collected it from dealer no.3 this afternoon, got halfway home and the noise was back! To me, it sounds as if something is trying to engage (possibly disengage?) from the front wheel, but I don't know much about Jeep systems (its my first Jeep!) It's a great car (when working!lol) and it would be a shame if I had to get rid of it. Any help/suggestions would be much appreciated.

[WhiteOut]

Have they cracked open the front diff?  Checked to front diff fluid?

[limey.ca]

I've been told that all fluid levels are fine, although there is a smell of hot oil (possibly transmission fluid) from the r/h side of the engine when its warm. The last dealer it went in to, has suggested that it may need a new diff - but I don't know how closely they looked or whether this is just a guess from them (either way its been quoted as approx $4000).

[JackstandJohnny]

sounds like a jeep.................. swap in a solid front axle

[FullMetalJeep]

sounds like a jeep.................. swap in a solid front axle

X2, man that would be a sexy new GC!! 2" lift and some 31's

[hps4evr]

i wonder if a bad pinion bearing is causing an issue. we had a couple front ends on these pooch out at my dealership. i wonder if my dealer was one of the three...
anyways. is this full time 4wd? if you can select see if it will do it in different ranges. drive down a straight street and back left to right and see if the noise changes.
maybe even a rock in the caliper, sounds dumb but we had 4 different grand cherokees with a gawdawful noise and all it turned out to be wasa small rock caught in the caliper.
weird eh;)

[JackstandJohnny]

trade you my 00 Grand Cherokee straight up. it doens't make any grinding noises at all