bevel gear/transfer case question/ and front cv suggestion

[Ronman]

Hello there,
My bevel gear went out on my 2005 xc70. 80,000. miles. Pulled it off. Here is what I found (see pics). It looks like the (male) splines insert of the bevel drive is stripped AS WELL AS the internal drive (female) splines that comes off the transmission. Is this normal? Does this mean I have to replace the complete transmission as well because of the internally worn splines in pic two? Even if I put a new transfer case on, that female section will always be weak and ready to strip the new splines on the transfer case.

No wonder these things fail. Based upon this finding, I would NEVER buy a used XC70 with a replaced bevel gear, because the internal splines off the tranny could also be half worn and waiting to strip out the new transfer case.
Secondly, There didnt appear to be any lubrication of the splines at all, meaning that if Im right, it doesnt matter how much you change the front bevel gear oil anyway ( or what precious gear oil you use) because the area of failure is a separate area. Is that correct?

Any thoughts?

Also..unrelated, but check it out. in pic three I found an easy way to change a front CV joint. just remove the brake caliper and the front two bolts of the a arm assembly and swing the whole thing back. This gives room to slide out the cv joint from the front bearing assembly. No need to undo joints, ABS, rotor ass. etc..

Cheers (as I contemplate a new tranny)... and how much does that cost anyway? Looks like I just lost $5000 or so. yay!


http://s27.photobucket.com/albums/c198/DUALRESPONSE1731/?action=view&current=IMG_4066.jpg

http://s27.photobucket.com/albums/c198/DUALRESPONSE1731/?action=view&current=IMG_4068.jpg

http://s27.photobucket.com/albums/c198/DUALRESPONSE1731/?action=view&current=IMG_4068.jpg

Thanks
Ron

[Ronman]

oh yeah, my links didnt work, except for one, but if you go there, you can scroll forward and backward to see all 3 pics.

[Ronman]

UPDATE:
I called the dealer and the worn piece on the tranny is called the bevel gear coupler. Fortunately, it doesnt require transmission rebuild to access and, It is fairly simple to replace. Evidently, these things fair all the time in the winter according to dealer. Also, the splines that fail on the bevel gear/bevel gear coupler are independent of the bevel gear itself and the oil that gets replaced, meaning, that you could pretty much replace your bevel gear oil with volvo's oil, mobil, or even toothpaste, and the splines will still last/fail on their own accord. The bevel gear itself seems pretty robust. Has anyone ever seem that fail? Seems like the splines are the weakpoint, not the actual bevel gear.

My bevel gear splines were covered in rust and it appears that at one time, the moisture got into the spline area through the drive axle assembly. I hit a deep patch of standing water one night several months ago, but doubt it had enough time to cause this much fuss.

From what Ive learned, I would suggest avoiding deep water to keep this area dry, and to never "flog" or go "rooting" in offroad or in the snow in an xc70. This aint no ford bronco, and will not withstand such torture. Drive in snow like you are on eggshells. ( I was never one to torture a car, but Im gonna be extra careful from now on).

Also, does anyone know if the transfer case design was changed with the new/latest model? Im looking for an excuse to buy a new one.

If only I could put a subaru 4 wheel drive system on the volvo chassis... Then Id be in heaven!

Later,
R

[JRL]

Collar gear, known weak point
Mostly on R with their higher torque but obviously on some XCs too [sly]
You are lucky.
If it was seized you would have needed a new transmission!!! :eek:

[Forkster]

I think your bevel gear may have developed a leak and ran dry. When ever I change my oil, I check the bevel gear for level and weeping.

Actually, the AWD system in the XC70 is fairly good. It's no Subaru, but it does a very good job in the winter time, coupled with traction control.

As a general rule of thumb, if you happen to go into water that submerges your drivetrain, it's always a good idea post-event to ensure you check the drivetrain and fluid levels. That comes from my military days as part of our post-op checklists and AWD funtimes with friends.

[onseytote]

UPDATE:
.....My bevel gear splines were covered in rust and it appears that at one time, the moisture got into the spline area through the drive axle assembly and transfer cases (http://www.mwdauto.com)...

From what Ive learned, I would suggest avoiding deep water ...

Later,
R

I think I just invited moisture. Is there anything to help with the rust?

[pelagikos]

Collar gear is intentionally made of softer steel than that in bevel gear and transmission shafts.
It is designed to be a less expensive failure point.
The idea is, if, for example, something goes wrong with the bevel gear, it might too destroy this simple, inexpensive an relatively easy to replace piece, instead of ravaging the transmission.

Of course, it does not always work out this way, but that’s another story.

In Ronman’s case, it actually appears to have worked as intended.

[carboncow]

Hello there,
My bevel gear went out on my 2005 xc70. 80,000. miles.
Ron

Ron,

Looks like your photos are gone but I was wondering how you figured this out.

I just bought a used 2003 XC70 and everything check out great until we put the new tires on it and tried to take it up a hill at work and determined there is no rear wheel help.

Did a test by lifting the front wheel while in N and spinning the tire and we could see the bevel gear was working as the shaft was spinning.

How does one know the spline is striped out? Was there a nasty sound? Can it be slipping underload even knowing a no load test show the shaft moving?

So many questions about this fun little spine!

Did you source the spline via volvo or another source?

[Astro14]

Carbon Cow - I am not sure your diagnosis is complete. I don't own a Haldex car, but from discussion threads, there are a host of electrical reasons that the haldex might not engage in your "test" or on your drive at work.

I would run those other possibilities down before pulling the gear out and replacing a spline that may, or may not, be stripped out...

[carboncow]

Carbon Cow - I am not sure your diagnosis is complete. I don't own a Haldex car, but from discussion threads, there are a host of electrical reasons that the haldex might not engage in your "test" or on your drive at work.

I would run those other possibilities down before pulling the gear out and replacing a spline that may, or may not, be stripped out...


Thanks Astro...I read all night and it does sound like the 2003 with electronic haldex does have some failure points with the pressure switch, pump and to an expensive degree the DEM.

I won't be pulling any bevel gear w/o testing these items first and have a knockoff Vida Dice already on the way.

The one thing I'm trying to rule out with low tech solutions is if the prop shaft can spin (from testing) but then slip from a bad spline under load. I would assume something like that would make a grinding noise though...and I have no bevel noise.

I did the onboard diagnostic and it does appear the DEM is offline...so we'll cross our fingers for a cheaper fix there first!