I did inspect the ring very closely. There is 3 very faint marks on it. None of which give me any pause about the serviceability of the part. They could be orders of magnitude worse before worrying about them.

I did note a bit of magnetic foreign material on the tip of the speed sensor which is fairly strongly magnetic. I didn't notice it until after pulling the sensor out and fishing it over the top of the diff and out of the way. That leaves the opportunity to have picked up some other foreign debris, but unlikely.


If I had to describe the noise, it would be imagine a diff assembled dry and not filled with lube. Then imagine how it would sound before the bearings heated up and self destructed. Kind of a hiss. Its not real loud, you can't hear it in the cabin with the windows up. The noise doesn't travel through the chassis. Its unrelated to load at all.


I'm thinking to hook up a chassis ear to a pico scope and get a few captures. Being able to visualize the sounds may shed some light on it.

__________________

90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff