My daughter's 98 V70 XC has 123,000 miles on the odometer. We have owned it for 9 months and expected to spend some money on the car given their reputation.

Recently the car developed a noise very similar to road noise from a tire, a loud whirring or muffled roar. It starts at 35 mph and sounds as if it is coming from the front right wheel area or passenger's floor board.

On the interstate, the noise is loudest at 65 mph but at 70 mph starts to subside quickly. Slow down to 65 and it is very loud again.

I know that the usual suspects include the bevel gear and the drive shaft, and I am prepared to replace either should it be necessary. What I don't want to do is replace expensive parts unnecessarily.

I decided to take the car to the dealer and let them diagnose the noise. The mechanic said it is the front right hub bearing. That would be great if that's all it turns out to be, but I'm not so confident because turning the wheel has no effect on the noise at all. The only thing other than speed that affects the noise is incline. It seems to decrease while climbing steep grades on the highway.

If I remove the drive shaft that should tell me if the problem is in drive shaft, but will it completely clear the bevel gear?

I have already purchased a new hub kit from Tasca, but I would like to have a diagnosis I trust before I take things apart. I would hate to do it again right away in order to get to the bevel gear if the hub bearing turns out to NOT be the problem.

The Volvo mechanic said the front CV-joint on the drive shaft looks like it has lost some grease. Any way I can get some grease in that joint long enough to drive it and see if it affects the noise?

Suggestions for how to approach this would be appreciated.


AG

What you described is bearing noise, the mechanic is correct. You cannot add grease to a leaking CV boot. Because you are already replacing the hub, do the axle at the same time. It is better to replace the axle than temporarily replace a boot.

Klaus
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1967 220 belonging to C.A. lives on

Thanks for the reply Klaus. I hope it is the hub bearing.

I'm sorry if I wasn't clear, but the axle boot isn't leaking. The mechanic claims the front cv-joint of the drive shaft is losing grease. They suggested replacing with Volvo part# 30651204 (but I will replace the entire drive shaft if that is the source of my problem). That's the joint I was hoping to temporarily lubricate.

Can removing the drive shaft cause a bad bevel gear to quiet down due to the lack of a load on the BG? If removing the drive shaft makes the noise disappear, can I be certain the problem was somewhere downline from the bevel gear?

I'm looking for the best way to troubleshoot a noisy BG short of replacing it.

Ahhh. Yes. The front CV joint can be greased, with regular CV grease. The hard part is getting a syringe to pump it in. Sounds like the CVV got too hot and melted the grease to a liquid.

You can easily replace the CV joint yourself, it has been known to fail in some cars. Easier if all 4 wheels are off the ground. I suspect repeated slipping and then hard grabbing on dry surfaces puts it through too much stress.

The best thing you can do for the bevel gear is to flush it every 30-50K miles. Do not wait for it to start leaking out of the filler hole.

Klaus
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1967 220 belonging to C.A. lives on