Hello folks. I'm looking into this a little for a friend. They have a Volv0 740dl, not sure of the year off the top of my head (mid 80's?).

The diff seems to drag a bit (although in a straight line), and sounds a bit rough. I didn't drive it much, but they claim its pretty bad; supposedly this is a fairly common problem with the 740's? I'm curious if this is well identified weak point.
Is there a common fix? Should the whole diff be replaced, or is there a simpler way? (new ring? new pinion? new bearings? etc)

Thanks,
Andrew

Sounds like the rear carrier bearings and/or ring gear are locking up, check the fluid level for correct amount and for any meatl shavings after youve driven the car a few miles. Check the fluid in bright light(outside in sun will work) and see if the oil looks like metallic paint, you know with sparkles in it. If it looks like bass boat sparkle its shot, lol. It will not be cheap to replace bearings and reset the rear diff so it may be cheaper to just swap in a junkyard rear end.

never heard of the rear ends ever going in these cars...but if its gone...its gone. snag one from a junkyard, by FAR the cheapest and easiest route to go. also, check your center bearing first...they can go and if there gone enough make a vibration/sound.