Reply With QuoteI think the leaking and the spline ring failure are the most. Actual gear failure is reported very little.
With the increasing number of failures and buzz on this item, I thought an overview might be in order.The angle gear, sometimes called bevel gear, is the gearset at the back of the front differential that "turns" the east-west motion of the front components to north-south (front to back) motion to spin the driveshaft.
It is a purely mechanical device with no clutches. It is similar in principle to the rear-end gears of the R and all RWD only cars.
It is not part of the Haldex system in any way other than the driveshaft is the input to the Haldex AOC. It always turns whenever the front wheels turn. The on/off of the rear axle to acheive AWD is done by the Haldex AOC.
It turns at at an RPM that is equal to the transmission output speed. Assuming no losses, it must handle up to 1000 lb ft of Torque in 1st gear.
Currently, there are 3 known failure modes, I believe they have no relation to each other.
1 - weeping fluid. The breather was redesigned to solve this
2 - failure of the pair of gears themselves.
3 - there has been one report (amongst SS owners) of an input shaft failureA simple test for 2 & 3 is to put the car in Neutral, turn the front wheels, and watch that the driveshaft turns. This should be diagnostic step #1 on any car with AWD failure.
I think the leaking and the spline ring failure are the most. Actual gear failure is reported very little.
Repair Details, as given to owners by dealers, are not differentiating between spline ring and gearset failures usually it seems.
Jim,
Given that most of the angle/bevel gear issues are only with seeping/leaking, are there any contributing factors to leaking that might excel the failure of the bevel gear? Would it be accurate to say that a persons driving habits might influence the failure/leaking of the bevel gear? Is leaking just a random occurance?KVB
Quote, originally posted by KVB » Jim,
Given that most of the angle/bevel gear issues are only with seeping/leaking, are there any contributing factors to leaking that might excel the failure of the bevel gear? Would it be accurate to say that a persons driving habits might influence the failure/leaking of the bevel gear? Is leaking just a random occurance?I can only speak for myself on this one....
I have no real leaks. I get at worst a weep when tracking the car. I have almost 1000 miles of track time, no failures.
If the car is driving without any issues, is there anything we can do or check for? Preventatively speaking.
Quote, originally posted by steamboatsig » If the car is driving without any issues, is there anything we can do or check for? Preventatively speaking. Nothing other to to check the fluid level I guess...
Is dripping fluid a sign of a pending failure?
Ah....yes! Keep an eye on it, and take it to the dealer at earliest opportunity!
another thing to mentions...the angle gear unit is $$$. My dealer told me retail cost is c.lose to $2000.so if yours is leaking, or may go bad, I'd get it fixed BEFORE the warranty expires.
Realistically, if the failure is occurring in vehicles with moderate mileage there should be some transfer of ownership of the problem to Volvo. I had the gear fail in my wife's previous 2000 XC at ~ 82K miles and now with the R at ~ 55K miles.
This seems to indicate some design or subcontractor part issue that VoNA should step up to the plate and help owners out with (as they did with my R).
I appreciate what they did for me but feel that there is some investigation to be done.
I am due for my 22K mile service at the end of the month. I will have them check it out. I noticed a spot of oil on the driveway yesterday morning.I will also have them check out my crappy AM reception and my leaking power steering reservoir.
thanks Jim for taking the time to do this, I had been wondering what the heck the thing was
Where does the leak occur? I have a leak on my 04v70R that is located on the inboard side of the front passenger side wheel. The leak is about 15cm (6 inches) from the inside of the wheel. Could this be the bevel gear or do you think it could be something else.Thanskf or you help.
Quote, originally posted by jov1605 » Where does the leak occur? I have a leak on my 04v70R that is located on the inboard side of the front passenger side wheel. The leak is about 15cm (6 inches) from the inside of the wheel. Could this be the bevel gear or do you think it could be something else. Thanks for your help.
You can find the angle gear box at the front of the driveshaft.... your leak sounds like the steering rack.
I'm surprised that no one reacted to this statement:
Quote, originally posted by JimLill » It turns at at an RPM that is equal to the transmission output speed. Assuming no losses, it must handle up to 1000 lb ft of Torque in 1st gear.
Thanks, but I doubt it is the steering as the leak is on the passenger side. However, you have hopefully confirmed it is not the bevel gear.
Quote, originally posted by jov1605 » Thanks, but I doubt it is the steering as the leak is on the passenger side. However, you have hopefully confirmed it is not the bevel gear. If leak is at END of rack, it can be either side.......
If is at the end of course it could be either side. I will have it checked. Much appreciated.
Jim,My 2004 V 70 R GT has shown increasing gear howl. I believe this is another failure mode, due to case flex, allowing gears to mesh too near the toe. Now at ~45,000, been noisy for ~10,000. First, is bustup coming, and second, any input from factory on recall or adjuastment?
Senilesurfer
As I have not had anything but weepage, I have no real first-hand insight into this........
Quote, originally posted by JimLill » I'm surprised that no one reacted to this statement: Quote, originally posted by JimLill »
It turns at at an RPM that is equal to the transmission output speed. Assuming no losses, it must handle up to 1000 lb ft of Torque in 1st gear.Jim,
That did get my attention. From a dynamics point of view, the variable rotational force from the front differential is acting on the length of the drive shaft. So, in first gear we see the max torque on the angle gear. The gear ratio has to be much higher just to get the car moving according to spec (or close), therefore, the high torque value.
To put it in simple terms.
2005 V70R Sapphire Black, Gobi Sand Interior
Mods: Bell FMIC, MTE Stage II, CAI, Track Spec Sways, TME DP w/ Custom Exhaust, Blue Max II Boost/EGT Electronic Gauge
Media, Etc iMIV w/ IPOD and XM, Hardwired Escort 8500 X50 Blue and Garmin 360 GPS
Mileage, Condition 120k mi, Very Good
Do other AWD systems such as the Mitsubishi Evolutions(transversly mounted engine as well) have to transfer power to the rear wheels by way of an angle gear? I searched for angle/bevel gear on google and they ALL lead back to swedespeed... leading me to believe that Volvo's are the only ones that use angle gears in their AWD system.And how do awd systems differ from engines that are mounted east/west(transversly) as opposed to cars with a traditional north/south setup like the boxer engines of the subarus/porsches and TT V6's of the B5 Audi S4?
Quote, originally posted by fightinchunk » Do other AWD systems such as the Mitsubishi Evolutions(transversly mounted engine as well) have to transfer power to the rear wheels by way of an angle gear? I searched for angle/bevel gear on google and they ALL lead back to swedespeed... leading me to believe that Volvo's are the only ones that use angle gears in their AWD system. And how do awd systems differ from engines that are mounted east/west(transversly) as opposed to cars with a traditional north/south setup like the boxer engines of the subarus/porsches and TT V6's of the B5 Audi S4?
From what I understand, the Angle gear or bevel gear is what Volvo calls their transfer case.
In a 4X4, where you can select whether or not you want 2wd or 4wd, the transfer case is adjustable, but serves essentially the exact same function as our Angle gear, except, our 'transfer case' is always set to 4wd. Some folk refer to this as the centre differential also.
From what I understand, its basically a differential that converts the motion coming out of the transmission from East/West to North/South so that power can be delivered through the driveshaft to the rear diff, where its converted to East/West again.
So every car with awd should in theory have an "angle gear" of sorts. Most are called center differentials though, I think.
Experts please feel free to correct/add to my shoddy diagram if I'm wrong.
My guess, based on what I gather: You have the front and rear differentials, which are open diffs (In audi and subaru, these are electronically lockable, computer controlled open diffs), and the centre differential, or angle gear, which is always locked. The haldex unit on the rearward end of the driveshaft controls how much power is pushed through to the rear diff.
In the Audi system, the "Torsen" centre diff is computer controlled and sends the power either to the front or to the back depending on need, and is usually under normal conditions set to some figure such as 50:50 split. My guess is that this "Torsen" is like our Angle gear and Haldex AOC rolled into one unit.
I'm hoping the experts on here will shed some more light on this, because most of my ideas are just educated guesses.
Modified by YK-GTR at 3:18 AM 3-31-2008
http://en.wikipedia.org/wiki/Haldex
This also answers the question about the difference between haldex and Torsen
Modified by YK-GTR at 3:21 AM 3-31-2008
Angle gear is also called a bevel gear. It is just a name for a gearset that turns the direction of motion 90 degrees. That function is used in many many vehicles. Any car that has a propshaft or driveshaft has some form of that gearset.The angle gear failures in a Volvo are more related to the concentric input shaft arrangement than because it is a 90 degree turn.
Every 4WD or AWD car every made has some form of this gearset.
Quote, originally posted by JimLill » Angle gear is also called a bevel gear. It is just a name for a gearset that turns the direction of motion 90 degrees. That function is used in many many vehicles. Any car that has a propshaft or driveshaft has some form of that gearset. The angle gear failures in a Volvo are more related to the concentric input shaft arrangement than because it is a 90 degree turn.
Every 4WD or AWD car every made has some form of this gearset.
Jim:
In that case, every RWD car has one too...it's called the rear differential.
Quote, originally posted by Needsdecaf » Jim:
In that case, every RWD car has one too...it's called the rear differential.
True but a differential adds function and complexity beyond just the right hand turn.
The angle gear is a cheap way of making a fwd car with a transversely mounted engine into 4wd.
The spline sleave and angle gear have to cope with enormous amounts of stress as they provide power to 3 of the 4 wheels, if the spline sleave fails you end up with a 1 wheel drive car.
I've recently had my angle gear and sleave replaced due to the angle gear leaking, the SM told me that the new sleaves are now hardend more and should hopefully last a lot longer.
Quote, originally posted by russ » The angle gear is a cheap way of making a fwd car with a transversely mounted engine into 4wd.
The spline sleave and angle gear have to cope with enormous amounts of stress as they provide power to 3 of the 4 wheels, if the spline sleave fails you end up with a 1 wheel drive car.
I've recently had my angle gear and sleave replaced due to the angle gear leaking, the SM told me that the new sleaves are now hardend more and should hopefully last a lot longer.Actually, it's the only way to make a transversely mounted engine into an AWD car, not just the cheap way.
Quote, originally posted by Needsdecaf » Actually, it's the only way to make a transversely mounted engine into an AWD car, not just the cheap way.
That is what I'm saying, if you have designed and manufactured fwd cars and then want to add an awd to your range of cars without major redesign costs, then the angle gear is one of the quickest and cheapest ways to do it.
What's the Best Method of Changing the Oil in those Units ?
Quote, originally posted by EngTech » What's the Best Method of Changing the Oil in those Units ? IIRC, the "approved" method is tedious. A Mity-Vac might be better but even the vent is hard to access.
so the use of an angle gear isn't necessarily bad, just that volvo seemed to have designed somewhat flawed system... right? Im looking for specifics on mitsubishi's S- AWC system right now... apparently they use a set of "spider gears". Im assuming this is their angle gear, correct?
Quote, originally posted by fightinchunk » apparently they use a set of "spider gears". Im assuming this is their angle gear, correct? Maybe not..... spyder gears often refer to a differential system.... if they have full-time AWD, they may have a diff scheme.
S-AWC can adjust drive torque at each wheel by controlling a network of dynamic handling technologies, including an Active Center Differential (ACD) 4-wheel drive, an Active Yaw Control (AYC) rear differential, Active Stability Control (ASC), and an anti-lock brake system (ABS).
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