Wheel bearing vs Bevel gear noise

**mitek_75** · 12-06-2007, 03:45 PM

Does anyone know the difference between the noises that a failing bevel gear makes comparing to the failing wheel bearing? My car has developed a strange noise (kind of humming + whistling at the same time) coming from the front that occurs only at slow speeds and when slightly accelerating. The noise goes away as soon as I get off the accelerator. I jacked up the front of my car for a quick inspection and it seems that the front driver’s side makes kind of a squeaky noise when I try to rotate the wheel and also the front drive shaft has a little side to side play.
Thanks.

**msir1995** · 12-06-2007, 09:24 PM

The whitsle noise might be your turbo

**PierreC** · 12-07-2007, 08:26 AM

Originally Posted by mitek_75

Does anyone know the difference between the noises that a failing bevel gear makes comparing to the failing wheel bearing? My car has developed a strange noise (kind of humming + whistling at the same time) coming from the front that occurs only at slow speeds and when slightly accelerating. The noise goes away as soon as I get off the accelerator. I jacked up the front of my car for a quick inspection and it seems that the front driver’s side makes kind of a squeaky noise when I try to rotate the wheel and also the front drive shaft has a little side to side play.
Thanks.

Switch off the aircon - if the noise disappears, have the aircon compressor checked out. Had a situation very similar to what you describe [humming + whistling at the same time] on my S60 and the aircon compressor needs to be replaced (currently on order).

A wheel bearing groans - it is a fairly low pitched noise - if it is whistling i.e. high pitched, it is unlikely but not impossible to be a wheel bearing.

**JAGMAN** · 12-08-2007, 02:44 PM

It is normal for drive shafts to have some movement inline with the shaft (1-2"). Shafts should have no play perpendicular to the shaft's axis.

**mitek_75** · 12-09-2007, 01:29 AM

Thanks everyone for replies. The air-conditioning does not affect the noise. I guess the drive shaft is ok then. I will have to take it to the dealer to figure out the noise. I hope it is not the bevel gear since it is expensive to fix and the car (04) has 88000km - out of warranty.

**mitek_75** · 02-14-2008, 04:31 PM

Just an update. 2004 xc70 with 90000km.
Well, it appears my transfer case is shot and that is the cause of the noise I have had for a while. My mechanic says the oil in the transfer case was wrong and that caused the bearing (connecting to the drive shaft) to seize and spin in the housing. So I guess I am paying the price for buying a used car. I was lucky the mechanic had a used unit out of a totaled 2005 xc70 with only 20000km on it, so he is changing the seals and installing it on my car. Still costs me $1700 for the unit. I hope it will last for another 90000km.

**tapanitja** · 02-15-2008, 12:16 AM

Hi,
feel sorry for your transmission, but sence we share the same worry:
how to take care of the awd transmission chain ie bevel, differential and Haldex for oil and filters if any. which oil and how often. I have -30deg.C to +30deg.C temperature span every year making condension and would chainge the oil despite Volvo-maintenance-non-guidance.
Makes me wondering if you have wrong oli in tranny, which is then used in bevel, Haldex and differential? Expensive components all as you stated.
br Tapani
ps. usinf old type ATF causes usually poor gear connectivity but that it's bearing lubrication would be poor? and cause spinning?
Could it be originally over heating causing to seize and spin? due to poor cooling as filter got blocked up. Is there any?

**Omega5** · 02-15-2008, 06:50 AM

I'm not an expert at this, but from my readings and understanding, the "special ATF" or the 3309 is different then say Dex II/III ,Merc and what not in the way the clutch plates friction against each other, not in it's lubricating properties.
This would be the first case I have ever heard of a low speed bearing (submerged in some type of oil none the less) seized because the wrong type of oil. No oil, YES i heard of it, but wrong type of oil, on a low speed bearing ... nahh i don't believe it. Sorry.

**JRL** · 02-15-2008, 08:34 AM

Originally Posted by Omega5

I'm not an expert at this, but from my readings and understanding, the "special ATF" or the 3309 is different then say Dex II/III ,Merc and what not in the way the clutch plates friction against each other, not in it's lubricating properties.
This would be the first case I have ever heard of a low speed bearing (submerged in some type of oil none the less) seized because the wrong type of oil. No oil, YES i heard of it, but wrong type of oil, on a low speed bearing ... nahh i don't believe it. Sorry.

I would have thought the same but I just had the lovely experience of a leaking bevel gear.
Upon inspection the leak was probably worse than it is now and someone put 90 weight gear oil in it to slow the leakage and sell it!
Needless to say when the oil came out, the gear was shot!
A "simple" reseal (sure it's $500) now is a $2500-$3000 replacement

(I gave the car back).

As for 3309 in a 4 speed tranny, that is used for a sometime hard shifting transmission, sometimes it works, sometimes not, but it can't do any harm either way which has nothing to do with this conversation

**Omega5** · 02-15-2008, 09:36 AM

JRL: I don't condone using fluids other then what is recommended by the manufacturer (unless they are equivalent) but what I am saying is that for a BEARING to fail because of the wrong oil, that's odd, specially for it to fail catastrophically not just wear prematurely.

From a mechanical perspective, to seize a bearing you need to 1) overheat the crap out of them 2)run them dry and even then you might not seize them. I mean a high speed bearing, OK, they are very sensitive, like those around the turbo I'd imagine are pretty delicate, but a bearing around a drive shaft ... that's a heavy duty low speed bearing.

Mind you, it happened, so you can't argue with that!

As for the bevel gear, how do you do routine inspection on that? I'd like to get a feel for what condition mine is in, any recommendations on how to do a quick inspection, what to look for and so on?