2000 XC70 - AWD?

3wagons · Post by **3wagons** » 10 Nov 2009, 10:26

Hello all. Outstanding forum!!

My Dilemma:
I just purchased a 2000 xc70 w/ 146,000 miles. The wagon is in very nice, (remarkable really,) condition inside and out. It has been dealer maintained, so mechanically is quite nice also.
With one exception- in town the car drives wonderful, but on the highway after about 10 or so minutes it begins to make a howling or buzzing kind of sound. It gets louder and louder until it sounds like a jet engine, not quite that loud but a similar sound. It seems to be at it's worst between 60-65. Next morning when it's cool- no noise then after a bit on the highway, noise is back. Then for remainder of commute, the noise is present at all speeds getting louder as speed increases.
Tires are all matched and same tread depth. I crawled under it and noticed a sticker and bar code on the propeller shaft dated Sep 07, it appears to be a genuine Volvo part, so that's not likely to be the issue. I didn't notice any leaks around the bevel gear housing or VC or anywhere else. The front axles have good boots and no typical clicking CV noise. Transmission fluid level is good and the color seems to be OK.
I have searched and searched but didn't find any threads that sounded like just the same problem.
Many have noise accompanied by clunking or vibration, but I don't seem to notice that. I couldn't really tell if it was coming from front or back, center or one side? Also, there is a squeak (from the rear?) when shifting from reverse to forward, but not from forward to reverse.
Apologies if this is tiresome or I have overlooked it being covered elsewhere. Thanks in advance for any help.

C@lvin · Post by **C@lvin** » 10 Nov 2009, 12:38

This may be of no help whatsoever, but I once had a windshield replaced and afterwards had an extremely loud howling type noise at highway speeds because the technician left a trim piece slightly loose. It was not really visible when you looked at it, but it was just loose enough for the wind to catch it and create a very loud, unpleasant noise. Plus, you couldn't really identify from within the cabin just where the noise was coming from.

Japedo · Post by **Japedo** » 10 Nov 2009, 13:09

hey 3 wagons, welcome to the forum! Or maybe u were here before as 2 wagons lol.
Unfortunantley I am kind of lost as to what advice to give you. I have the same awd drivetrain in my 01 XC and haven't had any of your symptoms.
I am wondering if possibly a worn rear differential could get noist as it heated up! maybe low on gear oil? driveshaft u joint?
Other things that create loud noise are wheelbearings, but you would notice handeling problems and the noise would be there around town as well.
Once you have your car making this noise, you say the noise goes up and down with the engine's rpm's. Did u try revving the engine in neutral once it's to this point?? If it didn't make the noise at this point, not moveing in neutral revving engine then u would know that the noise is coming from a moving part of the driveline.
Again, this was a stab in the dark, good luck

and welcome!

Post by **JRL** » 10 Nov 2009, 15:43

If it's a loud pitched whine, it may be the rear end

3wagons · Post by **3wagons** » 10 Nov 2009, 16:29

Thanks for the replies.

When I was on the highway, I shifted into nuetral and shut the motor off and the whining noise was still there. It doesn't change with engine speed. It seems like it's a driveline thing, just not sure where. Don't think it's a wheel bearing though.

Didn't check the fluid level in BG housing- good idea. Or rear end either.
JRL- It sounds like it could be a rear end. Now that you mention it thats kinda the type of noise it is. Is there a way to check it?

Anxious to get cleared up and back on the road daily, but won't be able to spend time on it until this weekend.

Thanks again for input.

P.S. Calvin- My 850 wagon had a trim piece above windsheild that was loose and made the strange noise you're refering to. Must be somewhat common. Lol.

Post by **holler1** » 10 Nov 2009, 16:44

This is a little drastic, but to see if it is something in the drivetrain from front to back, or more likely eliminate that as the problem, you could remove the front to rear driveshaft and try driving it as a 2wd. Before doing that, it might be worth checking to see if the rear diff is dry and/or if there is any grease leakage around it, and just take a general look under the car at all the AWD drivetrain components.

habstb · Post by **habstb** » 10 Nov 2009, 19:47

Sad to say, but sure as the sun will rise, your bevel gear is toast. I recently experienced the same jet engine sound that is absent when cold, but slowly appears once the car warms up. I removed the bevel gear and rear drive shaft and now drive FWD. Sadly, these parts are unique to the 2000 model year and you will not find a healthy used or rebuilt part. Volvo really blew it on these cars and they are not willing to come clean. You'll find references to this problem on just about any volvo forum or lemon web search. New replacement parts are worth far more than the value of the car. On the bright side, the car seems to perform OK in FWD - just waiting for the snow.