So I got the '86 245 DL running, about 230,000 miles. It has a very noticeable humm from the rear of the car. The humm starts out right away and is speed dependent. You can get it vary with appication of power, but coasting is still quite noticable. I was just under the car- literally and found the following:

The center driveline support has quite a bit of play in the rubber section- you can easily move this a 3/8 inch in any direction. Im told this is normal???

The u-joints seem to be tight and the center support bearing seems to be smooth

The rear bushing on the trailing arms ( under the axle tube) are obviously shot, as I support the body and jack the rear axle assembly up- I get about 1/2 inch of play vertical. The rest of the suspension bushings have little if any play

****Can the combination of these two problems result in driveline vibrations? My guess it that the rear axle pinion angle is shifting under load. ?????

How much does it cost to have a shop do the bushings- I see you need a special tool ( I do pretty much all my own work, but this looks to need tools that may not be worth investing in) ?????

Any help is appreciated

Mike- back under the car....