Glad I pulled off the rear output shaft bearing retainer to have a look for what damage was done. The driveshaft rattled the output shaft of the transfer, explaining the leak which I thought was just the speedo cable initially, and then the output seal. This is what it did to the bearing race and shim. The driveshaft wobble cut the shim up.
The recent history of the driveline is, I changed rear axle housing, springs, diif was fine. I probably didn't take enough care lubing the driveshaft, I did it, but not consciously enough. The driveshaft unijoint is stiff in one direction on the transfer side.
Did a fair bit of heavy 2t towing over some very bad roads. So the driveshaft rattled loose, all four bolts were still on. Explaining the over 80kmh vibration, after going over and checking virtually every front suspension, tyre and steering component.
Also, the transfer started filling from the oil of the transmission. I put one of those hose equalizer bandaids for now. All coincided with the heavy towing and consequent driveshaft vibration.
Biggest lesson learnt, check driveshaft bolts regularly, grease driveshaft consciously. Especially after heavy towing.
For now, I shall re- shim the bearing race and new uni and re-balance the driveshaft from the pros. Not worth me trying to balance a driveshaft on an iffy transfer bearing myself. The transfer oil drain plug magnet had some fine metal swarf, which makes sense with the shim grinding away.
At the very least, I am up for a transfer rebuild, new bearings. I have a 2000km round trip for work coming up in a 2 weeks, not sure if I can muster the parts and tools before the trip to do the rebuild before. Be good to have the kukko internal bearing puller.
Am I taking too much of a chance on the that transfer bearing?