1999 V70R AWD Horrid Rear Suspension/Drivetrain Clunk

[swedewrench]

Also, if you remove the propeller shaft and the noise goes away, you indeed are getting power to the rear wheels. How does the car react when driven on the rack? All four wheels spinning? Also have seen the engine mount on the R/F subframe, under the harmonic balancer cause issues on the AWD versions.

[tranmkp]

Ill jump in as my issue is very similar but there is no loud clunk.

99xc 70 - 120k - all drive train new - everything. here is a high pitched whine while underway - its starts at 10 mph and stays constant. It stops completely at 10 mph. Start and it comes on at 10 mph... Sitting in rear passenger seat - open the door and you can clearly hear it - its is coming from the rear diff/VC area.

I have no clue. VC is new, diff has been deemed fine. New colorado DS, BG is clean and fluid is clear. Tires are matched - emergency brakes are fine and have no effect on sound while underway.

Car drives insanely well, volvo dealer (could not hear it...) ran codes and found nothing, but decided to replace expansion valve in ac as it made a similar sound.

Thats it...

[breesay1]

I'm still in the middle of my attempt to fix this. But... I had a similar sound happening as my angle gear started to go bad. It sounded like a brake pad rubbing. Very scratchy and light. Since I removed the prop shaft (to roll FWD only for the moment) the sound disappeared completely. Give that a try perhaps and then you'll at least know if it's drivetrain related

[breesay1]

OK Gents, drumroll... it was the angle/bevel gear. Here is the breakdown of what happened.

1) When I dropped the bevel gear out of the car, the connector sleeve to the transmission was completely fine. The angle/bevel gear appeared to be working fine as well. When I spun the connector sleeve the output side of the angle gear that connects to the prop shaft spun at twice the rate as it should. Everything looked to be ok. The oil inside was rather viscous, but didn't contain any metal flakes. Then, I realized that if held the prop-shaft side of the angle gear very firmly that I could get spin the transmission sleeve side freely: BUSTED ANGLE GEAR. When I opened the unit up (out of curiosity mostly) it up, sure enough, although it was in fine shape and the and not worn in any way the large pinion gear was spinning freely around the shaft it mounts to. I believe this is the glued-in-place pinion- gear to shaft interface that everyone talks about.

2) So, I went to the local junkyard, pulled a clean angle gear with no leaks and nice clean gear oil in it ($200) and installed it on the my R. The removal and install we both fairly easy (with a friend who has professional lift). I had to remove from the old bevel gear and reinstall on the new bevel gear the prop-shaft-side connector since it was a slightly different configuration than the original. It has something like a 16mm nut holding it in place a and swapped out easily.

3) We'll see how it drives, but for the moment the AWD is gripping like vise on gravel, and the all drivetrain noises are gone. I did not replace anything else yet (prop shaft, viscous coupler, etc).

Thanks everyone for your help. We'll see how this one lasts...