Bevel Gear Leak ?

[2002CROSSCOUNTRY]

Bought a 2002 Cross Country a few weeks ago. I really like it and my wife rarely shows much liking for any car, but she love this one. It's getting 27 to 30 mpg which impresses me for such a solid car.

Never owned anything like a Volvo before, mostly Mustangs and GM Trucks. So needing to learn a lot.

I put the vehicle on stands and checked that the rear wheels turn in drive, they do turn. So I assume bevel gear and AWD is OK. But I noticed some leakage around the bevel gear/trans mating area. Looks kind of rust colored and not much of it.

Is this the bevel gear leaking or something from above seaping down ?

Also, I will check the fluid level. Should it be to the bottom of the plug ? And what kind of fluid goes in there ?

I have a feeling that I am gonna need a lot of help with this CrossCountry.

Thanks in advance.

[Xheart]

A how-to document http://www.volvoxc.com/resources/how-to/pdf/01-23-09/TNN,%20Drivetrain%20-%20Angle%20Gear%20Fluid%20Leakage.pdf

A relevant topic http://www.volvoxc.com/forums/showthread.php?t=20611

[2002CROSSCOUNTRY]

XHeart,

Thanks for the links, whatever it is leaking - it is very slow now, none hitting the pavement as far as I have seen.

I am curious about why the color is rusty orange, doesnt look like gear lube that I have ever seen.

[Astro14]

Got a picture? Could be leaking from above, could be anther fluid...

One thing that I learned (from this forum) was that I had been overfilling the bevel gear, so mine weeps, it's probably still a bit overfilled...

I have yet to do it, but the correct fill is a volume, not level with the plug, it works out to about 100ml below the fill plug (don't ask me why...unlike every other car I've ever owned...). so, you can top it off, then siphon out 100ml with a mityvac...

I learned a lot from Howard - a forum member who built his own site: http://www.freewebs.com/howardsvolvos/

I would spend some time on his site...

Cheers,

[howardc64]

Likely something seeping down. Bevel gear (aka angle gear) leaks seems to just make a oily mess on the angle gear housing itself. Little hard to orient from the pics because they are so close up. Seems to be in and around the transmission. The reddish/rusty color should be a give away. ATF is red and I think the only fluid that is corrosive to most metals is brake fluid.

Snap some shots from above and no so close up pics for easier orientation might give us a bit more hint

[Xheart]

I have yet to do it, but the correct fill is a volume, not level with the plug, it works out to about 100ml below the fill plug (don't ask me why...unlike every other car I've ever owned...). so, you can top it off, then siphon out 100ml with a mityvac...

This is in my to-do list.
I recall the procedure says to use Mityvac Vacuum Pump for extracting ALL of the fluid (0.75 liter), YES?

And then refill with 0.75 liter of Volvo Transmission Oil. Is this oil MOBIL 3309?

[Astro14]

Bevel gear uses a 75W90 gear oil (vs. 20WT trans fluid).

You can buy the Volvo oil for about $28/QT from your dealership (ouch) but looking at the can I bought, it's a GL-5 synthetic...and Mobil ONE 75W90 is $10.99/QT at my local Advance Auto Parts...

[2002CROSSCOUNTRY]

Thanks for all the comments.

I think maybe it is something leaking from above, I'll take a look for that and let you know what I find.

I found the spec for the volvo angle gear fluid and it API GL5, BOT Anyone know what the BOT is ?

[Davidatthepoint]

Isn't that GL 5 synthetic the same as for the rear diff? I wonder why both Volvo and IPD sell different oils for the angle gear and rear diff?

[Astro14]

GL-5 is a spec for gear lube...like SM for motor oil...

So, I suspect (but don't know) that there is a friction modifier in the angle gear lube since there is likely (again, don't know, haven't had it apart) a limited slip clutch.

The M1 75W90 has friction modifier in it...and friction modified gear oil won't hurt the rear diff...

I use the M1 in the Toyota's differentials, neither of which are limited slip, and both of which look great at 230K...

[billr99]

So, I suspect (but don't know) that there is a friction modifier in the angle gear lube since there is likely (again, don't know, haven't had it apart) a limited slip clutch.

Astro:

No clutch in the bevel gear. Its a simple spiral bevel gear set designed to redirect rotation from the line of the front axle perpendicular to the fore-aft prop shaft. Limited slip capability, if any, is taken care of by the VC or Haldex unit (depending on MY).

So with that said, nothing special about Volvo Gear Lube beyond the GL-5 syn-oil spec. I suspect that they specified the GL-5 lube not so much due to the gear set design, but due to the proximity of the bevel gear to the heat of the exhaust system. If that housing had been located somewhere like the rear end, it could have had the same GL-3 spec as any other bevel gear set. Interestingly, GL-5 is generally not recommended for LSD diffs unless the gear set is designed to a particular specification. Generally GL-5 is specified for hypoid gears (here is the Wiki on bevel gear type http://en.wikipedia.org/wiki/Hypoid_gear) used in extreme conditions. There is a GL-5LS spec that presumably adds something to the additive mix to accommodate LSDs.

Cheers,

Bill

[Astro14]

Thanks Bill - always wondered, but never pursued the answer...so, since it's just a spiral gear - all it needs is a good gear oil...

[billr99]

Thanks Bill - always wondered, but never pursued the answer...so, since it's just a spiral gear - all it needs is a good gear oil...

Yeah, kind of "more than you ever wanted to know about bevel gears"!:D And nothing "magical" about Volvo engineering, I'm afraid.

As I said, GL-5 spec lube should do it. Volvo, just like every other auto manufacturer, adheres to SAE design specs and guidelines. To go outside of those specs for a special, one-off purpose is pretty rare. On the other hand, the marketing potential behind using "special stuff" in their cars is out there as well. So you, as Volvo or whoever, put readily available fluids into your own packaging with your part number on it and you tell your customers that they are only to use those fluids because they have been "specially engineered to the demands of our unique design" . Then you put a high price tag on it to justify the "special". Nice part for us as consumers is that all auto fluids are required to label their true SAE specification so we as smart consumers can go out and get the same stuff, without the manufacturer packaging, for a more realistic price.

Years ago I met a guy who was a manager in the IT department at McLaren Racing. This is when they were being sponsored by Mobil 1 and had that splashed all over the car. Their print advertising went on and on about the multi-grade benefits of Mobil 1 in competition engines, etc, etc. According to this guy, and he had no reason to lie, the oil McLaren actually used was a straight weight caster oil. And not even from Mobil but from Castrol. And it was the same oil that all the UK-based teams used, had been using for years and what the engines were designed to use. But sponsorship is what gives these teams the ability to run the series, engineering and cost management is what runs the cars. I don't see the OEMs doing much different.

Cheers,

Bill